81878394 has 32 divisors (see below), whose sum is σ = 180661824. Its totient is φ = 24577920.

The previous prime is 81878393. The next prime is 81878441. The reversal of 81878394 is 49387818.

It is not an unprimeable number, because it can be changed into a prime (81878393) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9604 + ... + 15999.

It is an arithmetic number, because the mean of its divisors is an integer number (5645682).

Almost surely, 2^81878394 is an apocalyptic number.

81878394 is an abundant number, since it is smaller than the sum of its proper divisors (98783430).

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

81878394 is a wasteful number, since it uses less digits than its factorization.

81878394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25662.

The product of its digits is 387072, while the sum is 48.

The square root of 81878394 is about 9048.6680787837. The cubic root of 81878394 is about 434.2332801237.

It can be divided in two parts, 81 and 878394, that added together give a triangular number (878475 = T₁₃₂₅).

The spelling of 81878394 in words is "eighty-one million, eight hundred seventy-eight thousand, three hundred ninety-four".