817522997991 has 8 divisors (see below), whose sum is σ = 1245749330304. Its totient is φ = 467155998840.

The previous prime is 817522997969. The next prime is 817522998001. The reversal of 817522997991 is 199799225718.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 817522997991 - 2⁶ = 817522997927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (817522997911) 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, 19464833265 + ... + 19464833306.

It is an arithmetic number, because the mean of its divisors is an integer number (155718666288).

Almost surely, 2^817522997991 is an apocalyptic number.

817522997991 is a deficient number, since it is larger than the sum of its proper divisors (428226332313).

817522997991 is a wasteful number, since it uses less digits than its factorization.

817522997991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38929666581.

The product of its digits is 51438240, while the sum is 69.

The spelling of 817522997991 in words is "eight hundred seventeen billion, five hundred twenty-two million, nine hundred ninety-seven thousand, nine hundred ninety-one".