656020921 has 2 divisors, whose sum is σ = 656020922. Its totient is φ = 656020920.

The previous prime is 656020793. The next prime is 656020993. The reversal of 656020921 is 129020656.

656020921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 501267321 + 154753600 = 22389^2 + 12440^2 .

It is a cyclic number.

It is not a de Polignac number, because 656020921 - 2⁷ = 656020793 is a prime.

It is not a weakly prime, because it can be changed into another prime (656029921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328010460 + 328010461.

It is an arithmetic number, because the mean of its divisors is an integer number (328010461).

Almost surely, 2^656020921 is an apocalyptic number.

It is an amenable number.

656020921 is a deficient number, since it is larger than the sum of its proper divisors (1).

656020921 is an equidigital number, since it uses as much as digits as its factorization.

656020921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 656020921 is about 25612.9053603842. The cubic root of 656020921 is about 868.9055339353.

The spelling of 656020921 in words is "six hundred fifty-six million, twenty thousand, nine hundred twenty-one".