81163878 has 16 divisors (see below), whose sum is σ = 162791856. Its totient is φ = 26977280.

The previous prime is 81163861. The next prime is 81163909. The reversal of 81163878 is 87836118.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17043 + ... + 21278.

It is an arithmetic number, because the mean of its divisors is an integer number (10174491).

Almost surely, 2^81163878 is an apocalyptic number.

81163878 is an abundant number, since it is smaller than the sum of its proper divisors (81627978).

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

81163878 is a wasteful number, since it uses less digits than its factorization.

81163878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38679.

The product of its digits is 64512, while the sum is 42.

The square root of 81163878 is about 9009.0997330477. The cubic root of 81163878 is about 432.9664683252.

The spelling of 81163878 in words is "eighty-one million, one hundred sixty-three thousand, eight hundred seventy-eight".