56807981 has 2 divisors, whose sum is σ = 56807982. Its totient is φ = 56807980.

The previous prime is 56807969. The next prime is 56807983. The reversal of 56807981 is 18970865.

It is a happy number.

56807981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28622500 + 28185481 = 5350^2 + 5309^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-56807981 is a prime.

It is a super-2 number, since 2×56807981² = 6454293410592722, which contains 22 as substring.

Together with 56807983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56807983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28403990 + 28403991.

It is an arithmetic number, because the mean of its divisors is an integer number (28403991).

Almost surely, 2^56807981 is an apocalyptic number.

It is an amenable number.

56807981 is a deficient number, since it is larger than the sum of its proper divisors (1).

56807981 is an equidigital number, since it uses as much as digits as its factorization.

56807981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120960, while the sum is 44.

The square root of 56807981 is about 7537.1069383418. The cubic root of 56807981 is about 384.4174717737.

The spelling of 56807981 in words is "fifty-six million, eight hundred seven thousand, nine hundred eighty-one".