81125918692 has 96 divisors (see below), whose sum is σ = 177936175872. Its totient is φ = 31510757376.

The previous prime is 81125918641. The next prime is 81125918707. The reversal of 81125918692 is 29681952118.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4391908 + ... + 4410340.

It is an arithmetic number, because the mean of its divisors is an integer number (1853501832).

Almost surely, 2^81125918692 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81125918692, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88968087936).

81125918692 is an abundant number, since it is smaller than the sum of its proper divisors (96810257180).

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

81125918692 is a wasteful number, since it uses less digits than its factorization.

81125918692 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18677 (or 18675 counting only the distinct ones).

The product of its digits is 622080, while the sum is 52.

The spelling of 81125918692 in words is "eighty-one billion, one hundred twenty-five million, nine hundred eighteen thousand, six hundred ninety-two".