645183756 has 72 divisors (see below), whose sum is σ = 1868848800. Its totient is φ = 183845376.

The previous prime is 645183743. The next prime is 645183797. The reversal of 645183756 is 657381546.

645183756 is a `hidden beast` number, since 64 + 518 + 3 + 75 + 6 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 96820 + ... + 103268.

Almost surely, 2^645183756 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645183756, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (934424400).

645183756 is an abundant number, since it is smaller than the sum of its proper divisors (1223665044).

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

645183756 is a wasteful number, since it uses less digits than its factorization.

645183756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6863 (or 6858 counting only the distinct ones).

The product of its digits is 604800, while the sum is 45.

The square root of 645183756 is about 25400.4676334905. The cubic root of 645183756 is about 864.0943023355.

The spelling of 645183756 in words is "six hundred forty-five million, one hundred eighty-three thousand, seven hundred fifty-six".