644704332 has 24 divisors (see below), whose sum is σ = 1539295296. Its totient is φ = 209903568.

The previous prime is 644704331. The next prime is 644704363. The reversal of 644704332 is 233407446.

It is a junction number, because it is equal to n+sod(n) for n = 644704293 and 644704302.

It is not an unprimeable number, because it can be changed into a prime (644704331) 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, 624198 + ... + 625229.

It is an arithmetic number, because the mean of its divisors is an integer number (64137304).

Almost surely, 2^644704332 is an apocalyptic number.

It is an amenable number.

644704332 is an abundant number, since it is smaller than the sum of its proper divisors (894590964).

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

644704332 is a wasteful number, since it uses less digits than its factorization.

644704332 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1249477 (or 1249475 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 33.

The square root of 644704332 is about 25391.0285731004. The cubic root of 644704332 is about 863.8802185199.

The spelling of 644704332 in words is "six hundred forty-four million, seven hundred four thousand, three hundred thirty-two".