81133808 has 60 divisors (see below), whose sum is σ = 184050720. Its totient is φ = 34546176.

The previous prime is 81133783. The next prime is 81133813. The reversal of 81133808 is 80833118.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 187160 + ... + 187592.

It is an arithmetic number, because the mean of its divisors is an integer number (3067512).

Almost surely, 2^81133808 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 81133808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92025360).

81133808 is an abundant number, since it is smaller than the sum of its proper divisors (102916912).

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

81133808 is a wasteful number, since it uses less digits than its factorization.

81133808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 694 (or 681 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 81133808 is about 9007.4307102525. The cubic root of 81133808 is about 432.9129925255.

The spelling of 81133808 in words is "eighty-one million, one hundred thirty-three thousand, eight hundred eight".