656432561 has 2 divisors, whose sum is σ = 656432562. Its totient is φ = 656432560.

The previous prime is 656432521. The next prime is 656432573. The reversal of 656432561 is 165234656.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 438693025 + 217739536 = 20945^2 + 14756^2 .

It is a cyclic number.

It is not a de Polignac number, because 656432561 - 2¹⁰ = 656431537 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (656432521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328216280 + 328216281.

It is an arithmetic number, because the mean of its divisors is an integer number (328216281).

Almost surely, 2^656432561 is an apocalyptic number.

It is an amenable number.

656432561 is a deficient number, since it is larger than the sum of its proper divisors (1).

656432561 is an equidigital number, since it uses as much as digits as its factorization.

656432561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 129600, while the sum is 38.

The square root of 656432561 is about 25620.9398929860. The cubic root of 656432561 is about 869.0872362139.

The spelling of 656432561 in words is "six hundred fifty-six million, four hundred thirty-two thousand, five hundred sixty-one".