644570613 has 12 divisors (see below), whose sum is σ = 942264960. Its totient is φ = 424535976.

The previous prime is 644570581. The next prime is 644570621. The reversal of 644570613 is 316075446.

It is a happy number.

644570613 is a `hidden beast` number, since 644 + 5 + 7 + 0 + 6 + 1 + 3 = 666.

It is not a de Polignac number, because 644570613 - 2⁵ = 644570581 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644570513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 430693 + ... + 432186.

It is an arithmetic number, because the mean of its divisors is an integer number (78522080).

Almost surely, 2^644570613 is an apocalyptic number.

It is an amenable number.

644570613 is a deficient number, since it is larger than the sum of its proper divisors (297694347).

644570613 is a wasteful number, since it uses less digits than its factorization.

644570613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 862968 (or 862965 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The square root of 644570613 is about 25388.3952427088. The cubic root of 644570613 is about 863.8204882008.

The spelling of 644570613 in words is "six hundred forty-four million, five hundred seventy thousand, six hundred thirteen".