644090220 has 72 divisors (see below), whose sum is σ = 2068676064. Its totient is φ = 161653248.

The previous prime is 644090219. The next prime is 644090233. The reversal of 644090220 is 22090446.

It is a super-2 number, since 2×644090220² = 829704422999296800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 102184 + ... + 108303.

It is an arithmetic number, because the mean of its divisors is an integer number (28731612).

Almost surely, 2^644090220 is an apocalyptic number.

644090220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

644090220 is an abundant number, since it is smaller than the sum of its proper divisors (1424585844).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644090220 is a wasteful number, since it uses less digits than its factorization.

644090220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210519 (or 210514 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 644090220 is about 25378.9326016679. The cubic root of 644090220 is about 863.6058355095.

The spelling of 644090220 in words is "six hundred forty-four million, ninety thousand, two hundred twenty".