81132239 has 4 divisors (see below), whose sum is σ = 83749440. Its totient is φ = 78515040.

The previous prime is 81132221. The next prime is 81132263. The reversal of 81132239 is 93223118.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81132239 - 2²⁴ = 64355023 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81132439) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1308554 + ... + 1308615.

It is an arithmetic number, because the mean of its divisors is an integer number (20937360).

Almost surely, 2^81132239 is an apocalyptic number.

81132239 is a deficient number, since it is larger than the sum of its proper divisors (2617201).

81132239 is a wasteful number, since it uses less digits than its factorization.

81132239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2617200.

The product of its digits is 2592, while the sum is 29.

The square root of 81132239 is about 9007.3436150732. The cubic root of 81132239 is about 432.9102018891.

The spelling of 81132239 in words is "eighty-one million, one hundred thirty-two thousand, two hundred thirty-nine".