81338432 has 84 divisors (see below), whose sum is σ = 193107564. Its totient is φ = 33868800.

The previous prime is 81338429. The next prime is 81338443. The reversal of 81338432 is 23483318.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 71503936 + 9834496 = 8456^2 + 3136^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 115682 + ... + 116382.

Almost surely, 2^81338432 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 81338432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96553782).

81338432 is an abundant number, since it is smaller than the sum of its proper divisors (111769132).

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

81338432 is a wasteful number, since it uses less digits than its factorization.

81338432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 764 (or 747 counting only the distinct ones).

The product of its digits is 13824, while the sum is 32.

The square root of 81338432 is about 9018.7821794298. The cubic root of 81338432 is about 433.2766305819.

The spelling of 81338432 in words is "eighty-one million, three hundred thirty-eight thousand, four hundred thirty-two".