81791717475 has 24 divisors (see below), whose sum is σ = 145631203312. Its totient is φ = 40266691200.

The previous prime is 81791717459. The next prime is 81791717519. The reversal of 81791717475 is 57471719718.

It is not a de Polignac number, because 81791717475 - 2⁴ = 81791717459 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41943496 + ... + 41945445.

Almost surely, 2^81791717475 is an apocalyptic number.

81791717475 is a deficient number, since it is larger than the sum of its proper divisors (63839485837).

81791717475 is a wasteful number, since it uses less digits than its factorization.

81791717475 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83888967 (or 83888962 counting only the distinct ones).

The product of its digits is 3457440, while the sum is 57.

The spelling of 81791717475 in words is "eighty-one billion, seven hundred ninety-one million, seven hundred seventeen thousand, four hundred seventy-five".