645827931 has 16 divisors (see below), whose sum is σ = 1093465600. Its totient is φ = 369044424.

The previous prime is 645827927. The next prime is 645827957. The reversal of 645827931 is 139728546.

645827931 is a `hidden beast` number, since 64 + 582 + 7 + 9 + 3 + 1 = 666.

It is not a de Polignac number, because 645827931 - 2² = 645827927 is a prime.

It is a super-2 number, since 2×645827931² = 834187432919481522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645827981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1708351 + ... + 1708728.

It is an arithmetic number, because the mean of its divisors is an integer number (68341600).

Almost surely, 2^645827931 is an apocalyptic number.

645827931 is a deficient number, since it is larger than the sum of its proper divisors (447637669).

645827931 is a wasteful number, since it uses less digits than its factorization.

645827931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3417095 (or 3417089 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 645827931 is about 25413.1448467127. The cubic root of 645827931 is about 864.3817877700.

The spelling of 645827931 in words is "six hundred forty-five million, eight hundred twenty-seven thousand, nine hundred thirty-one".