656897521 has 8 divisors (see below), whose sum is σ = 766713600. Its totient is φ = 551074848.

The previous prime is 656897497. The next prime is 656897539. The reversal of 656897521 is 125798656.

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

It is a cyclic number.

It is not a de Polignac number, because 656897521 - 2⁵ = 656897489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (656898521) 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, 997996 + ... + 998653.

It is an arithmetic number, because the mean of its divisors is an integer number (95839200).

Almost surely, 2^656897521 is an apocalyptic number.

It is an amenable number.

656897521 is a deficient number, since it is larger than the sum of its proper divisors (109816079).

656897521 is a wasteful number, since it uses less digits than its factorization.

656897521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1996703.

The product of its digits is 907200, while the sum is 49.

The square root of 656897521 is about 25630.0121147065. The cubic root of 656897521 is about 869.2923831730.

The spelling of 656897521 in words is "six hundred fifty-six million, eight hundred ninety-seven thousand, five hundred twenty-one".