656021231 has 2 divisors, whose sum is σ = 656021232. Its totient is φ = 656021230.

The previous prime is 656021207. The next prime is 656021237. The reversal of 656021231 is 132120656.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-656021231 is a prime.

It is a super-2 number, since 2×656021231² = 860727711045510722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 656021231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (656021237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328010615 + 328010616.

It is an arithmetic number, because the mean of its divisors is an integer number (328010616).

Almost surely, 2^656021231 is an apocalyptic number.

656021231 is a deficient number, since it is larger than the sum of its proper divisors (1).

656021231 is an equidigital number, since it uses as much as digits as its factorization.

656021231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 656021231 is about 25612.9114120203. The cubic root of 656021231 is about 868.9056708012.

Adding to 656021231 its reverse (132120656), we get a palindrome (788141887).

The spelling of 656021231 in words is "six hundred fifty-six million, twenty-one thousand, two hundred thirty-one".