So Archer is an animated sitcom based around the antics of it's eponymous hero, Sterling Archer. Sterling works for ISIS, a top-secret spy agency in the style of top-secret spy agencies all over, partly because it's run by his overbearing mother and partly because it's hard to imagine another line of work where his fondness for booze, women and violence would be an asset. Maybe Football? Also on the ISIS roster are it's accountant, Cyril, HR head Pam, Receptionist Cheryl (or Carol) and big-handed co-Agent Lana. A typical episode features some sort of lose justification for the team getting into trouble, and largely getting out it despite themselves.
At the risk of getting slightly off-topic, its worth noting here that out of the main cast, the majority (4 to 3) are women. If you count supporting regulars Ray and Kreiger as half-each (which in screen terms, is about right) then you have a setup here with even male-female ratios, and its depressing just how rare that is. But the thing is, Archer shows how this is a good thing in stark creative terms. Bear with me on this. So usually, you get shows with a strong bias one way or another depending on demographic, but usually its more men than women, and this locks in the female characters to certain roles, usually as the "straight man". This is simply because if you've only got one or two women in the cast they end up carrying the weight of the shows view on women; so they have to be safer.
Put it another way; there is a reason that The Big Bang Theory got a lot better when it integrated two more women in the main cast, which meant that Penny was allowed to get more depth, and didn't have to shoulder all the "female" plotlines the writers spewed up.
Back to Archer, you simply wouldn't have characters as novel and interesting and funny as Pam and Cheryl if they were the only women. Lana fits in the competent kill-joy role that seems to the default female role in ensembles these days (looks at Futurama) and Mallory is largely the tyrannical mother figure. But I just can't envision either of the other two working as male characters (as a lot of the humour around them is either transgressive (Cheryl) or unexpected (Pam)) nor being the sort of characters you'd want to lead the female half of the cast. Also, it frees up Mallory and Lana to go "off the reservation" a little more often.
None of this really has much to do with the main fact, which is that Archer is really, really funny. The Spy Agency setup is really the loosest of frameworks to justify sending the characters around the world and into all sorts of scrapes, and they live in a timeless, blended era that lets it mix-and-match its inspirations and spoofery on a whim. Its a clever show, acting dumb, and that's really hard to do. I've been consistently surprised by how it handles its characters, and often take off-guard by where its stories are going to go.
And its really, really funny. Did I mention that?