81132531 has 8 divisors (see below), whose sum is σ = 109134480. Its totient is φ = 53609472.

The previous prime is 81132521. The next prime is 81132533. The reversal of 81132531 is 13523118.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81132531 - 2²¹ = 79035379 is a prime.

It is a super-2 number, since 2×81132531² = 13164975172931922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81132533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 119326 + ... + 120003.

It is an arithmetic number, because the mean of its divisors is an integer number (13641810).

Almost surely, 2^81132531 is an apocalyptic number.

81132531 is a deficient number, since it is larger than the sum of its proper divisors (28001949).

81132531 is a wasteful number, since it uses less digits than its factorization.

81132531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239445.

The product of its digits is 720, while the sum is 24.

The square root of 81132531 is about 9007.3598240550. The cubic root of 81132531 is about 432.9107212455.

Adding to 81132531 its reverse (13523118), we get a palindrome (94655649).

The spelling of 81132531 in words is "eighty-one million, one hundred thirty-two thousand, five hundred thirty-one".