644252402 has 16 divisors (see below), whose sum is σ = 1031849280. Its totient is φ = 300954192.

The previous prime is 644252387. The next prime is 644252407. The reversal of 644252402 is 204252446.

It is a super-2 number, since 2×644252402² = 830122314965539208, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (644252407) 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, 160877 + ... + 164832.

It is an arithmetic number, because the mean of its divisors is an integer number (64490580).

Almost surely, 2^644252402 is an apocalyptic number.

644252402 is a deficient number, since it is larger than the sum of its proper divisors (387596878).

644252402 is a wasteful number, since it uses less digits than its factorization.

644252402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325777.

The product of its (nonzero) digits is 15360, while the sum is 29.

The square root of 644252402 is about 25382.1276097966. The cubic root of 644252402 is about 863.6783147798.

The spelling of 644252402 in words is "six hundred forty-four million, two hundred fifty-two thousand, four hundred two".