811921221976 has 32 divisors (see below), whose sum is σ = 1535136791040. Its totient is φ = 402554734848.

The previous prime is 811921221961. The next prime is 811921221983. The reversal of 811921221976 is 679122129118.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1757220 + ... + 2170636.

It is an arithmetic number, because the mean of its divisors is an integer number (47973024720).

Almost surely, 2^811921221976 is an apocalyptic number.

It is an amenable number.

811921221976 is a deficient number, since it is larger than the sum of its proper divisors (723215569064).

811921221976 is a wasteful number, since it uses less digits than its factorization.

811921221976 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415483 (or 415479 counting only the distinct ones).

The product of its digits is 217728, while the sum is 49.

The spelling of 811921221976 in words is "eight hundred eleven billion, nine hundred twenty-one million, two hundred twenty-one thousand, nine hundred seventy-six".