644074040 has 32 divisors (see below), whose sum is σ = 1454312880. Its totient is φ = 256714752.

The previous prime is 644074009. The next prime is 644074049. The reversal of 644074040 is 40470446.

It is a junction number, because it is equal to n+sod(n) for n = 644073994 and 644074012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644074049) 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, 17129 + ... + 39768.

Almost surely, 2^644074040 is an apocalyptic number.

It is an amenable number.

644074040 is an abundant number, since it is smaller than the sum of its proper divisors (810238840).

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

644074040 is a wasteful number, since it uses less digits than its factorization.

644074040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57191 (or 57187 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 29.

The square root of 644074040 is about 25378.6138313344. The cubic root of 644074040 is about 863.5986039866.

The spelling of 644074040 in words is "six hundred forty-four million, seventy-four thousand, forty".