81219953976 has 64 divisors (see below), whose sum is σ = 232079116800. Its totient is φ = 23203490688.

The previous prime is 81219953963. The next prime is 81219953987. The reversal of 81219953976 is 67935991218.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2704821 + ... + 2734683.

It is an arithmetic number, because the mean of its divisors is an integer number (3626236200).

Almost surely, 2^81219953976 is an apocalyptic number.

It is an amenable number.

81219953976 is an abundant number, since it is smaller than the sum of its proper divisors (150859162824).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81219953976 is a wasteful number, since it uses less digits than its factorization.

81219953976 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46068 (or 46064 counting only the distinct ones).

The product of its digits is 7348320, while the sum is 60.

The spelling of 81219953976 in words is "eighty-one billion, two hundred nineteen million, nine hundred fifty-three thousand, nine hundred seventy-six".