56610721 has 2 divisors, whose sum is σ = 56610722. Its totient is φ = 56610720.

The previous prime is 56610707. The next prime is 56610727. The reversal of 56610721 is 12701665.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50922496 + 5688225 = 7136^2 + 2385^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-56610721 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 56610721.

It is not a weakly prime, because it can be changed into another prime (56610727) 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, 28305360 + 28305361.

It is an arithmetic number, because the mean of its divisors is an integer number (28305361).

Almost surely, 2^56610721 is an apocalyptic number.

It is an amenable number.

56610721 is a deficient number, since it is larger than the sum of its proper divisors (1).

56610721 is an equidigital number, since it uses as much as digits as its factorization.

56610721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 56610721 is about 7524.0096358258. The cubic root of 56610721 is about 383.9720054281.

The spelling of 56610721 in words is "fifty-six million, six hundred ten thousand, seven hundred twenty-one".