81111672 has 64 divisors (see below), whose sum is σ = 227037600. Its totient is φ = 26830080.

The previous prime is 81111661. The next prime is 81111673. The reversal of 81111672 is 27611118.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81111673) 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, 28222 + ... + 30962.

Almost surely, 2^81111672 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 81111672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113518800).

81111672 is an abundant number, since it is smaller than the sum of its proper divisors (145925928).

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

81111672 is a wasteful number, since it uses less digits than its factorization.

81111672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2893 (or 2883 counting only the distinct ones).

The product of its digits is 672, while the sum is 27.

The square root of 81111672 is about 9006.2018631607. The cubic root of 81111672 is about 432.8736179257.

The spelling of 81111672 in words is "eighty-one million, one hundred eleven thousand, six hundred seventy-two".