645117959 has 4 divisors (see below), whose sum is σ = 646658040. Its totient is φ = 643577880.

The previous prime is 645117953. The next prime is 645118031. The reversal of 645117959 is 959711546.

645117959 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 645117959 - 2⁸ = 645117703 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645117953) 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, 769412 + ... + 770249.

It is an arithmetic number, because the mean of its divisors is an integer number (161664510).

Almost surely, 2^645117959 is an apocalyptic number.

645117959 is a deficient number, since it is larger than the sum of its proper divisors (1540081).

645117959 is a wasteful number, since it uses less digits than its factorization.

645117959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1540080.

The product of its digits is 340200, while the sum is 47.

The square root of 645117959 is about 25399.1724077774. The cubic root of 645117959 is about 864.0649273731.

The spelling of 645117959 in words is "six hundred forty-five million, one hundred seventeen thousand, nine hundred fifty-nine".