56005555991 has 16 divisors (see below), whose sum is σ = 70327461120. Its totient is φ = 43326722880.

The previous prime is 56005555987. The next prime is 56005555999. The reversal of 56005555991 is 19955550065.

56005555991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 56005555991 - 2² = 56005555987 is a prime.

It is a super-2 number, since 2×56005555991² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56005555999) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2605646 + ... + 2627051.

It is an arithmetic number, because the mean of its divisors is an integer number (4395466320).

Almost surely, 2^56005555991 is an apocalyptic number.

56005555991 is a deficient number, since it is larger than the sum of its proper divisors (14321905129).

56005555991 is a wasteful number, since it uses less digits than its factorization.

56005555991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5232854.

The product of its (nonzero) digits is 1518750, while the sum is 50.

The spelling of 56005555991 in words is "fifty-six billion, five million, five hundred fifty-five thousand, nine hundred ninety-one".