645696131 has 8 divisors (see below), whose sum is σ = 654438528. Its totient is φ = 637000000.

The previous prime is 645696109. The next prime is 645696173. The reversal of 645696131 is 131696546.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645696131 is a prime.

It is a super-2 number, since 2×645696131² = 833846987176738322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645696631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17006 + ... + 39756.

It is an arithmetic number, because the mean of its divisors is an integer number (81804816).

Almost surely, 2^645696131 is an apocalyptic number.

645696131 is a deficient number, since it is larger than the sum of its proper divisors (8742397).

645696131 is a wasteful number, since it uses less digits than its factorization.

645696131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23133.

The product of its digits is 116640, while the sum is 41.

The square root of 645696131 is about 25410.5515681970. The cubic root of 645696131 is about 864.3229830095.

The spelling of 645696131 in words is "six hundred forty-five million, six hundred ninety-six thousand, one hundred thirty-one".