56221172991 has 12 divisors (see below), whose sum is σ = 85985323632. Its totient is φ = 35276030016.

The previous prime is 56221172947. The next prime is 56221173007. The reversal of 56221172991 is 19927112265.

56221172991 is a `hidden beast` number, since 5 + 622 + 1 + 17 + 2 + 9 + 9 + 1 = 666.

It is not a de Polignac number, because 56221172991 - 2⁷ = 56221172863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56221172921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 183729171 + ... + 183729476.

It is an arithmetic number, because the mean of its divisors is an integer number (7165443636).

Almost surely, 2^56221172991 is an apocalyptic number.

56221172991 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

56221172991 is a deficient number, since it is larger than the sum of its proper divisors (29764150641).

56221172991 is a wasteful number, since it uses less digits than its factorization.

56221172991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 367458670 (or 367458667 counting only the distinct ones).

The product of its digits is 136080, while the sum is 45.

The spelling of 56221172991 in words is "fifty-six billion, two hundred twenty-one million, one hundred seventy-two thousand, nine hundred ninety-one".