81479947992 has 16 divisors (see below), whose sum is σ = 203699870040. Its totient is φ = 27159982656.

The previous prime is 81479947981. The next prime is 81479947993. The reversal of 81479947992 is 29974997418.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81479947993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1697498893 + ... + 1697498940.

Almost surely, 2^81479947992 is an apocalyptic number.

It is an amenable number.

81479947992 is an abundant number, since it is smaller than the sum of its proper divisors (122219922048).

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

81479947992 is a wasteful number, since it uses less digits than its factorization.

81479947992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3394997842 (or 3394997838 counting only the distinct ones).

The product of its digits is 82301184, while the sum is 69.

The spelling of 81479947992 in words is "eighty-one billion, four hundred seventy-nine million, nine hundred forty-seven thousand, nine hundred ninety-two".