81989244 has 54 divisors (see below), whose sum is σ = 211959384. Its totient is φ = 26722320.

The previous prime is 81989231. The next prime is 81989263. The reversal of 81989244 is 44298918.

It is a super-2 number, since 2×81989244² = 13444472263383072, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81989244.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 79009 + ... + 80039.

Almost surely, 2^81989244 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 81989244, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105979692).

81989244 is an abundant number, since it is smaller than the sum of its proper divisors (129970140).

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

81989244 is a wasteful number, since it uses less digits than its factorization.

81989244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1135 (or 1083 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The square root of 81989244 is about 9054.7912179133. The cubic root of 81989244 is about 434.4291521191.

The spelling of 81989244 in words is "eighty-one million, nine hundred eighty-nine thousand, two hundred forty-four".