81179880 has 128 divisors (see below), whose sum is σ = 258508800. Its totient is φ = 20351232.

The previous prime is 81179873. The next prime is 81179881. The reversal of 81179880 is 8897118.

It is not an unprimeable number, because it can be changed into a prime (81179881) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 184701 + ... + 185139.

It is an arithmetic number, because the mean of its divisors is an integer number (2019600).

Almost surely, 2^81179880 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 81179880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129254400).

81179880 is an abundant number, since it is smaller than the sum of its proper divisors (177328920).

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

81179880 is a wasteful number, since it uses less digits than its factorization.

81179880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 543 (or 539 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 42.

The square root of 81179880 is about 9009.9877913347. The cubic root of 81179880 is about 432.9949205313.

The spelling of 81179880 in words is "eighty-one million, one hundred seventy-nine thousand, eight hundred eighty".