56591221 has 2 divisors, whose sum is σ = 56591222. Its totient is φ = 56591220.

The previous prime is 56591219. The next prime is 56591231. The reversal of 56591221 is 12219565.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55800900 + 790321 = 7470^2 + 889^2 .

It is a cyclic number.

It is not a de Polignac number, because 56591221 - 2¹ = 56591219 is a prime.

Together with 56591219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56591231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28295610 + 28295611.

It is an arithmetic number, because the mean of its divisors is an integer number (28295611).

Almost surely, 2^56591221 is an apocalyptic number.

It is an amenable number.

56591221 is a deficient number, since it is larger than the sum of its proper divisors (1).

56591221 is an equidigital number, since it uses as much as digits as its factorization.

56591221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5400, while the sum is 31.

The square root of 56591221 is about 7522.7136726051. The cubic root of 56591221 is about 383.9279129909.

The spelling of 56591221 in words is "fifty-six million, five hundred ninety-one thousand, two hundred twenty-one".