81138132 has 48 divisors (see below), whose sum is σ = 221435200. Its totient is φ = 25621920.

The previous prime is 81138131. The next prime is 81138133. The reversal of 81138132 is 23183118.

It is an interprime number because it is at equal distance from previous prime (81138131) and next prime (81138133).

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

It is a junction number, because it is equal to n+sod(n) for n = 81138096 and 81138105.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81138131) 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, 17719 + ... + 21822.

Almost surely, 2^81138132 is an apocalyptic number.

It is an amenable number.

81138132 is an abundant number, since it is smaller than the sum of its proper divisors (140297068).

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

81138132 is a wasteful number, since it uses less digits than its factorization.

81138132 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39573 (or 39565 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 81138132 is about 9007.6707311047. The cubic root of 81138132 is about 432.9206830414.

The spelling of 81138132 in words is "eighty-one million, one hundred thirty-eight thousand, one hundred thirty-two".