81381432 has 32 divisors (see below), whose sum is σ = 221950080. Its totient is φ = 24660960.

The previous prime is 81381403. The next prime is 81381437. The reversal of 81381432 is 23418318.

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

It is a self number, because there is not a number n which added to its sum of digits gives 81381432.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81381437) 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, 153868 + ... + 154395.

It is an arithmetic number, because the mean of its divisors is an integer number (6935940).

Almost surely, 2^81381432 is an apocalyptic number.

It is an amenable number.

81381432 is an abundant number, since it is smaller than the sum of its proper divisors (140568648).

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

81381432 is a wasteful number, since it uses less digits than its factorization.

81381432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308283 (or 308279 counting only the distinct ones).

The product of its digits is 4608, while the sum is 30.

The square root of 81381432 is about 9021.1657783238. The cubic root of 81381432 is about 433.3529684725.

The spelling of 81381432 in words is "eighty-one million, three hundred eighty-one thousand, four hundred thirty-two".