646385931 has 12 divisors (see below), whose sum is σ = 941021952. Its totient is φ = 427530096.

The previous prime is 646385921. The next prime is 646385941. The reversal of 646385931 is 139583646.

646385931 is a `hidden beast` number, since 6 + 4 + 638 + 5 + 9 + 3 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (646385921) and next prime (646385941).

It is not a de Polignac number, because 646385931 - 2⁵ = 646385899 is a prime.

It is a super-2 number, since 2×646385931² = 835629543589473522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (646385921) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 281616 + ... + 283901.

It is an arithmetic number, because the mean of its divisors is an integer number (78418496).

Almost surely, 2^646385931 is an apocalyptic number.

646385931 is a deficient number, since it is larger than the sum of its proper divisors (294636021).

646385931 is a wasteful number, since it uses less digits than its factorization.

646385931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 565650 (or 565647 counting only the distinct ones).

The product of its digits is 466560, while the sum is 45.

The square root of 646385931 is about 25424.1210467540. The cubic root of 646385931 is about 864.6306601452.

The spelling of 646385931 in words is "six hundred forty-six million, three hundred eighty-five thousand, nine hundred thirty-one".