644081172 has 48 divisors (see below), whose sum is σ = 1772961792. Its totient is φ = 178086240.

The previous prime is 644081161. The next prime is 644081183. The reversal of 644081172 is 271180446.

It is an interprime number because it is at equal distance from previous prime (644081161) and next prime (644081183).

It is a super-2 number, since 2×644081172² = 829681112249787168, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 121068 + ... + 126275.

It is an arithmetic number, because the mean of its divisors is an integer number (36936704).

Almost surely, 2^644081172 is an apocalyptic number.

644081172 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

It is an amenable number.

644081172 is an abundant number, since it is smaller than the sum of its proper divisors (1128880620).

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

644081172 is a wasteful number, since it uses less digits than its factorization.

644081172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247388 (or 247386 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 33.

The square root of 644081172 is about 25378.7543429539. The cubic root of 644081172 is about 863.6017915925.

The spelling of 644081172 in words is "six hundred forty-four million, eighty-one thousand, one hundred seventy-two".