81879512 has 64 divisors (see below), whose sum is σ = 189907200. Its totient is φ = 32538240.

The previous prime is 81879487. The next prime is 81879521. The reversal of 81879512 is 21597818.

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 81879512.

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, 19853 + ... + 23619.

It is an arithmetic number, because the mean of its divisors is an integer number (2967300).

Almost surely, 2^81879512 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 81879512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94953600).

81879512 is an abundant number, since it is smaller than the sum of its proper divisors (108027688).

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

81879512 is a wasteful number, since it uses less digits than its factorization.

81879512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3816 (or 3812 counting only the distinct ones).

The product of its digits is 40320, while the sum is 41.

The square root of 81879512 is about 9048.7298556206. The cubic root of 81879512 is about 434.2352565124.

The spelling of 81879512 in words is "eighty-one million, eight hundred seventy-nine thousand, five hundred twelve".