644251272 has 32 divisors (see below), whose sum is σ = 1840718400. Its totient is φ = 184071744.

The previous prime is 644251271. The next prime is 644251273. The reversal of 644251272 is 272152446.

644251272 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (644251271) and next prime (644251273).

It is not an unprimeable number, because it can be changed into a prime (644251271) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1917247 + ... + 1917582.

It is an arithmetic number, because the mean of its divisors is an integer number (57522450).

Almost surely, 2^644251272 is an apocalyptic number.

It is an amenable number.

644251272 is an abundant number, since it is smaller than the sum of its proper divisors (1196467128).

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

644251272 is a wasteful number, since it uses less digits than its factorization.

644251272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3834845 (or 3834841 counting only the distinct ones).

The product of its digits is 26880, while the sum is 33.

The square root of 644251272 is about 25382.1053500296. The cubic root of 644251272 is about 863.6778098239.

The spelling of 644251272 in words is "six hundred forty-four million, two hundred fifty-one thousand, two hundred seventy-two".