645311538 has 24 divisors (see below), whose sum is σ = 1446389100. Its totient is φ = 207686304.

The previous prime is 645311507. The next prime is 645311539. The reversal of 645311538 is 835113546.

645311538 is a `hidden beast` number, since 64 + 53 + 11 + 538 = 666.

645311538 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 606784689 + 38526849 = 24633^2 + 6207^2 .

It is not an unprimeable number, because it can be changed into a prime (645311539) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 617593 + ... + 618636.

Almost surely, 2^645311538 is an apocalyptic number.

645311538 is an abundant number, since it is smaller than the sum of its proper divisors (801077562).

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

645311538 is a wasteful number, since it uses less digits than its factorization.

645311538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1236266 (or 1236263 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 645311538 is about 25402.9828563498. The cubic root of 645311538 is about 864.1513446941.

The spelling of 645311538 in words is "six hundred forty-five million, three hundred eleven thousand, five hundred thirty-eight".