56611155721 has 2 divisors, whose sum is σ = 56611155722. Its totient is φ = 56611155720.

The previous prime is 56611155719. The next prime is 56611155743. The reversal of 56611155721 is 12755111665.

56611155721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29321767696 + 27289388025 = 171236^2 + 165195^2 .

It is a cyclic number.

It is not a de Polignac number, because 56611155721 - 2¹ = 56611155719 is a prime.

It is a super-2 number, since 2×56611155721² (a number of 22 digits) contains 22 as substring.

Together with 56611155719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (56611105721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28305577860 + 28305577861.

It is an arithmetic number, because the mean of its divisors is an integer number (28305577861).

Almost surely, 2^56611155721 is an apocalyptic number.

It is an amenable number.

56611155721 is a deficient number, since it is larger than the sum of its proper divisors (1).

56611155721 is an equidigital number, since it uses as much as digits as its factorization.

56611155721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 63000, while the sum is 40.

The spelling of 56611155721 in words is "fifty-six billion, six hundred eleven million, one hundred fifty-five thousand, seven hundred twenty-one".