643957165 has 8 divisors (see below), whose sum is σ = 772885728. Its totient is φ = 515074320.

The previous prime is 643957157. The next prime is 643957187. The reversal of 643957165 is 561759346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 643957165 - 2³ = 643957157 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 44074 + ... + 56836.

It is an arithmetic number, because the mean of its divisors is an integer number (96610716).

Almost surely, 2^643957165 is an apocalyptic number.

It is an amenable number.

643957165 is a deficient number, since it is larger than the sum of its proper divisors (128928563).

643957165 is a wasteful number, since it uses less digits than its factorization.

643957165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22859.

The product of its digits is 680400, while the sum is 46.

The square root of 643957165 is about 25376.3110991334. The cubic root of 643957165 is about 863.5463640337.

The spelling of 643957165 in words is "six hundred forty-three million, nine hundred fifty-seven thousand, one hundred sixty-five".