81878018 has 16 divisors (see below), whose sum is σ = 130636800. Its totient is φ = 38354496.

The previous prime is 81878009. The next prime is 81878021. The reversal of 81878018 is 81087818.

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, 2183 + ... + 12981.

It is an arithmetic number, because the mean of its divisors is an integer number (8164800).

Almost surely, 2^81878018 is an apocalyptic number.

81878018 is a deficient number, since it is larger than the sum of its proper divisors (48758782).

81878018 is a wasteful number, since it uses less digits than its factorization.

81878018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11041.

The product of its (nonzero) digits is 28672, while the sum is 41.

The square root of 81878018 is about 9048.6473022215. The cubic root of 81878018 is about 434.2326154308.

The spelling of 81878018 in words is "eighty-one million, eight hundred seventy-eight thousand, eighteen".