56516981 has 2 divisors, whose sum is σ = 56516982. Its totient is φ = 56516980.

The previous prime is 56516951. The next prime is 56516987. The reversal of 56516981 is 18961565.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40436881 + 16080100 = 6359^2 + 4010^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-56516981 is a prime.

It is a super-2 number, since 2×56516981² = 6388338282708722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56516987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28258490 + 28258491.

It is an arithmetic number, because the mean of its divisors is an integer number (28258491).

Almost surely, 2^56516981 is an apocalyptic number.

It is an amenable number.

56516981 is a deficient number, since it is larger than the sum of its proper divisors (1).

56516981 is an equidigital number, since it uses as much as digits as its factorization.

56516981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64800, while the sum is 41.

The square root of 56516981 is about 7517.7776636450. Note that the first 3 decimals coincide. The cubic root of 56516981 is about 383.7599524204.

The spelling of 56516981 in words is "fifty-six million, five hundred sixteen thousand, nine hundred eighty-one".