71056637991 has 8 divisors (see below), whose sum is σ = 105269093360. Its totient is φ = 47371091976.

The previous prime is 71056637983. The next prime is 71056638001. The reversal of 71056637991 is 19973665017.

It is a happy number.

71056637991 is a `hidden beast` number, since 7 + 1 + 0 + 566 + 3 + 79 + 9 + 1 = 666.

It is not a de Polignac number, because 71056637991 - 2³ = 71056637983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71056637191) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1315863640 + ... + 1315863693.

It is an arithmetic number, because the mean of its divisors is an integer number (13158636670).

Almost surely, 2^71056637991 is an apocalyptic number.

71056637991 is a deficient number, since it is larger than the sum of its proper divisors (34212455369).

71056637991 is a wasteful number, since it uses less digits than its factorization.

71056637991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2631727342 (or 2631727336 counting only the distinct ones).

The product of its (nonzero) digits is 2143260, while the sum is 54.

The spelling of 71056637991 in words is "seventy-one billion, fifty-six million, six hundred thirty-seven thousand, nine hundred ninety-one".