645188904 has 48 divisors (see below), whose sum is σ = 1765420020. Its totient is φ = 212843520.

The previous prime is 645188891. The next prime is 645188953. The reversal of 645188904 is 409881546.

It can be written as a sum of positive squares in 2 ways, for example, as 642622500 + 2566404 = 25350^2 + 1602^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 645188904.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 39207 + ... + 53174.

Almost surely, 2^645188904 is an apocalyptic number.

It is an amenable number.

645188904 is an abundant number, since it is smaller than the sum of its proper divisors (1120231116).

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

645188904 is a wasteful number, since it uses less digits than its factorization.

645188904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92490 (or 92483 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The square root of 645188904 is about 25400.5689700054. The cubic root of 645188904 is about 864.0966005674.

The spelling of 645188904 in words is "six hundred forty-five million, one hundred eighty-eight thousand, nine hundred four".