645291864 has 96 divisors (see below), whose sum is σ = 2084209920. Its totient is φ = 176349888.

The previous prime is 645291863. The next prime is 645291901. The reversal of 645291864 is 468192546.

645291864 is a `hidden beast` number, since 64 + 529 + 1 + 8 + 64 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645291863) 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 23 ways as a sum of consecutive naturals, for example, 16242 + ... + 39425.

It is an arithmetic number, because the mean of its divisors is an integer number (21710520).

Almost surely, 2^645291864 is an apocalyptic number.

It is an amenable number.

645291864 is an abundant number, since it is smaller than the sum of its proper divisors (1438918056).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645291864 is a wasteful number, since it uses less digits than its factorization.

645291864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55709 (or 55702 counting only the distinct ones).

The product of its digits is 414720, while the sum is 45.

The square root of 645291864 is about 25402.5956154091. The cubic root of 645291864 is about 864.1425626380.

The spelling of 645291864 in words is "six hundred forty-five million, two hundred ninety-one thousand, eight hundred sixty-four".