644660272 has 40 divisors (see below), whose sum is σ = 1342771200. Its totient is φ = 298861632.

The previous prime is 644660231. The next prime is 644660309. The reversal of 644660272 is 272066446.

It is a super-2 number, since 2×644660272² = 831173732590227968, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8272 + ... + 36847.

It is an arithmetic number, because the mean of its divisors is an integer number (33569280).

Almost surely, 2^644660272 is an apocalyptic number.

It is an amenable number.

644660272 is an abundant number, since it is smaller than the sum of its proper divisors (698110928).

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

644660272 is a wasteful number, since it uses less digits than its factorization.

644660272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45193 (or 45187 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 37.

The square root of 644660272 is about 25390.1609289898. The cubic root of 644660272 is about 863.8605384756.

The spelling of 644660272 in words is "six hundred forty-four million, six hundred sixty thousand, two hundred seventy-two".