56401561 has 2 divisors, whose sum is σ = 56401562. Its totient is φ = 56401560.

The previous prime is 56401559. The next prime is 56401567. The reversal of 56401561 is 16510465.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39137536 + 17264025 = 6256^2 + 4155^2 .

It is a cyclic number.

It is not a de Polignac number, because 56401561 - 2¹ = 56401559 is a prime.

It is a super-2 number, since 2×56401561² = 6362272166473442, which contains 22 as substring.

Together with 56401559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (56401567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28200780 + 28200781.

It is an arithmetic number, because the mean of its divisors is an integer number (28200781).

Almost surely, 2^56401561 is an apocalyptic number.

It is an amenable number.

56401561 is a deficient number, since it is larger than the sum of its proper divisors (1).

56401561 is an equidigital number, since it uses as much as digits as its factorization.

56401561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 56401561 is about 7510.0972696763. The cubic root of 56401561 is about 383.4985338783.

The spelling of 56401561 in words is "fifty-six million, four hundred one thousand, five hundred sixty-one".