81974113251 has 8 divisors (see below), whose sum is σ = 109353014544. Its totient is φ = 54622310400.

The previous prime is 81974113229. The next prime is 81974113283. The reversal of 81974113251 is 15231147918.

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

It is not a de Polignac number, because 81974113251 - 2¹⁵ = 81974080483 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81974114251) 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, 6767550 + ... + 6779651.

It is an arithmetic number, because the mean of its divisors is an integer number (13669126818).

Almost surely, 2^81974113251 is an apocalyptic number.

81974113251 is a deficient number, since it is larger than the sum of its proper divisors (27378901293).

81974113251 is a wasteful number, since it uses less digits than its factorization.

81974113251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13549221.

The product of its digits is 60480, while the sum is 42.

The spelling of 81974113251 in words is "eighty-one billion, nine hundred seventy-four million, one hundred thirteen thousand, two hundred fifty-one".