81889444 has 48 divisors (see below), whose sum is σ = 177146368. Its totient is φ = 32254848.

The previous prime is 81889441. The next prime is 81889513. The reversal of 81889444 is 44498818.

It is a junction number, because it is equal to n+sod(n) for n = 81889394 and 81889403.

It is not an unprimeable number, because it can be changed into a prime (81889441) 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, 133282 + ... + 133894.

Almost surely, 2^81889444 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 81889444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88573184).

81889444 is an abundant number, since it is smaller than the sum of its proper divisors (95256924).

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

81889444 is a wasteful number, since it uses less digits than its factorization.

81889444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1004 (or 1002 counting only the distinct ones).

The product of its digits is 294912, while the sum is 46.

The square root of 81889444 is about 9049.2786452844. The cubic root of 81889444 is about 434.2528134083.

The spelling of 81889444 in words is "eighty-one million, eight hundred eighty-nine thousand, four hundred forty-four".