644304740 has 24 divisors (see below), whose sum is σ = 1357141632. Its totient is φ = 256940640.

The previous prime is 644304691. The next prime is 644304779. The reversal of 644304740 is 47403446.

It is a junction number, because it is equal to n+sod(n) for n = 644304697 and 644304706.

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, 42044 + ... + 55283.

It is an arithmetic number, because the mean of its divisors is an integer number (56547568).

Almost surely, 2^644304740 is an apocalyptic number.

It is an amenable number.

644304740 is an abundant number, since it is smaller than the sum of its proper divisors (712836892).

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

644304740 is a wasteful number, since it uses less digits than its factorization.

644304740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97667 (or 97665 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 32.

The square root of 644304740 is about 25383.1585898997. The cubic root of 644304740 is about 863.7017020793.

The spelling of 644304740 in words is "six hundred forty-four million, three hundred four thousand, seven hundred forty".