56511721567 has 4 divisors (see below), whose sum is σ = 64584824656. Its totient is φ = 48438618480.

The previous prime is 56511721561. The next prime is 56511721601. The reversal of 56511721567 is 76512711565.

56511721567 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 76512711565 = 5 ⋅15302542313.

It is not a de Polignac number, because 56511721567 - 2³ = 56511721559 is a prime.

It is a super-2 number, since 2×56511721567² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56511721561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4036551534 + ... + 4036551547.

It is an arithmetic number, because the mean of its divisors is an integer number (16146206164).

Almost surely, 2^56511721567 is an apocalyptic number.

56511721567 is a deficient number, since it is larger than the sum of its proper divisors (8073103089).

56511721567 is an equidigital number, since it uses as much as digits as its factorization.

56511721567 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8073103088.

The product of its digits is 441000, while the sum is 46.

The spelling of 56511721567 in words is "fifty-six billion, five hundred eleven million, seven hundred twenty-one thousand, five hundred sixty-seven".