656051681 has 2 divisors, whose sum is σ = 656051682. Its totient is φ = 656051680.

The previous prime is 656051677. The next prime is 656051749. The reversal of 656051681 is 186150656.

656051681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 635846656 + 20205025 = 25216^2 + 4495^2 .

It is a cyclic number.

It is not a de Polignac number, because 656051681 - 2² = 656051677 is a prime.

It is a super-2 number, since 2×656051681² = 860807616285851522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (656051281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328025840 + 328025841.

It is an arithmetic number, because the mean of its divisors is an integer number (328025841).

Almost surely, 2^656051681 is an apocalyptic number.

It is an amenable number.

656051681 is a deficient number, since it is larger than the sum of its proper divisors (1).

656051681 is an equidigital number, since it uses as much as digits as its factorization.

656051681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43200, while the sum is 38.

The square root of 656051681 is about 25613.5058318849. The cubic root of 656051681 is about 868.9191143541.

The spelling of 656051681 in words is "six hundred fifty-six million, fifty-one thousand, six hundred eighty-one".