81673872 has 40 divisors (see below), whose sum is σ = 241133376. Its totient is φ = 23335296.

The previous prime is 81673859. The next prime is 81673873. The reversal of 81673872 is 27837618.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (81673873) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 121203 + ... + 121874.

Almost surely, 2^81673872 is an apocalyptic number.

It is an amenable number.

81673872 is an abundant number, since it is smaller than the sum of its proper divisors (159459504).

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

81673872 is a wasteful number, since it uses less digits than its factorization.

81673872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243095 (or 243089 counting only the distinct ones).

The product of its digits is 112896, while the sum is 42.

The square root of 81673872 is about 9037.3597914435. The cubic root of 81673872 is about 433.8714251703.

The spelling of 81673872 in words is "eighty-one million, six hundred seventy-three thousand, eight hundred seventy-two".