645164631 has 6 divisors (see below), whose sum is σ = 931904480. Its totient is φ = 430109748.

The previous prime is 645164593. The next prime is 645164659. The reversal of 645164631 is 136461546.

It is a happy number.

645164631 is a `hidden beast` number, since 6 + 4 + 5 + 1 + 646 + 3 + 1 = 666.

It is not a de Polignac number, because 645164631 - 2⁷ = 645164503 is a prime.

It is a super-2 number, since 2×645164631² = 832474802186732322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645164231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35842471 + ... + 35842488.

Almost surely, 2^645164631 is an apocalyptic number.

645164631 is a deficient number, since it is larger than the sum of its proper divisors (286739849).

645164631 is a wasteful number, since it uses less digits than its factorization.

645164631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71684965 (or 71684962 counting only the distinct ones).

The product of its digits is 51840, while the sum is 36.

The square root of 645164631 is about 25400.0911612537. The cubic root of 645164631 is about 864.0857642166.

The spelling of 645164631 in words is "six hundred forty-five million, one hundred sixty-four thousand, six hundred thirty-one".