56721811 has 2 divisors, whose sum is σ = 56721812. Its totient is φ = 56721810.

The previous prime is 56721799. The next prime is 56721827. The reversal of 56721811 is 11812765.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 56721811 - 2¹¹ = 56719763 is a prime.

It is not a weakly prime, because it can be changed into another prime (56721871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28360905 + 28360906.

It is an arithmetic number, because the mean of its divisors is an integer number (28360906).

Almost surely, 2^56721811 is an apocalyptic number.

56721811 is a deficient number, since it is larger than the sum of its proper divisors (1).

56721811 is an equidigital number, since it uses as much as digits as its factorization.

56721811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3360, while the sum is 31.

The square root of 56721811 is about 7531.3883846207. The cubic root of 56721811 is about 384.2230036965.

The spelling of 56721811 in words is "fifty-six million, seven hundred twenty-one thousand, eight hundred eleven".