645868 has 12 divisors (see below), whose sum is σ = 1149232. Its totient is φ = 317520.

The previous prime is 645857. The next prime is 645877. The reversal of 645868 is 868546.

It is an unprimeable number.

645868 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1080 + ... + 1567.

2⁶⁴⁵⁸⁶⁸ is an apocalyptic number.

It is an amenable number.

645868 is a deficient number, since it is larger than the sum of its proper divisors (503364).

645868 is a wasteful number, since it uses less digits than its factorization.

645868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2712 (or 2710 counting only the distinct ones).

The product of its digits is 46080, while the sum is 37.

The square root of 645868 is about 803.6591317219. The cubic root of 645868 is about 86.4399663634.

The spelling of 645868 in words is "six hundred forty-five thousand, eight hundred sixty-eight".