644403652 has 24 divisors (see below), whose sum is σ = 1156167936. Its totient is φ = 314123328.

The previous prime is 644403559. The next prime is 644403701. The reversal of 644403652 is 256304446.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42928 + ... + 55960.

It is an arithmetic number, because the mean of its divisors is an integer number (48173664).

Almost surely, 2^644403652 is an apocalyptic number.

It is an amenable number.

644403652 is a deficient number, since it is larger than the sum of its proper divisors (511764284).

644403652 is a wasteful number, since it uses less digits than its factorization.

644403652 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13347 (or 13345 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 34.

The square root of 644403652 is about 25385.1068936099. The cubic root of 644403652 is about 863.7458975695.

The spelling of 644403652 in words is "six hundred forty-four million, four hundred three thousand, six hundred fifty-two".