645399624 has 32 divisors (see below), whose sum is σ = 1614996000. Its totient is φ = 214933632.

The previous prime is 645399607. The next prime is 645399647. The reversal of 645399624 is 426993546.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15187 + ... + 39005.

It is an arithmetic number, because the mean of its divisors is an integer number (50468625).

Almost surely, 2^645399624 is an apocalyptic number.

It is an amenable number.

645399624 is an abundant number, since it is smaller than the sum of its proper divisors (969596376).

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

645399624 is a wasteful number, since it uses less digits than its factorization.

645399624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24957 (or 24953 counting only the distinct ones).

The product of its digits is 1399680, while the sum is 48.

The square root of 645399624 is about 25404.7165699600. The cubic root of 645399624 is about 864.1906622266.

The spelling of 645399624 in words is "six hundred forty-five million, three hundred ninety-nine thousand, six hundred twenty-four".