645982923 has 4 divisors (see below), whose sum is σ = 861310568. Its totient is φ = 430655280.

The previous prime is 645982903. The next prime is 645982933. The reversal of 645982923 is 329289546.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 645982923 - 2⁵ = 645982891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645982903) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107663818 + ... + 107663823.

It is an arithmetic number, because the mean of its divisors is an integer number (215327642).

Almost surely, 2^645982923 is an apocalyptic number.

645982923 is a deficient number, since it is larger than the sum of its proper divisors (215327645).

645982923 is a wasteful number, since it uses less digits than its factorization.

645982923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215327644.

The product of its digits is 933120, while the sum is 48.

The square root of 645982923 is about 25416.1941092682. The cubic root of 645982923 is about 864.4509297916.

The spelling of 645982923 in words is "six hundred forty-five million, nine hundred eighty-two thousand, nine hundred twenty-three".