81531484 has 12 divisors (see below), whose sum is σ = 142822008. Its totient is φ = 40725200.

The previous prime is 81531433. The next prime is 81531487. The reversal of 81531484 is 48413518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81531487) 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, 5362 + ... + 13849.

It is an arithmetic number, because the mean of its divisors is an integer number (11901834).

Almost surely, 2^81531484 is an apocalyptic number.

It is an amenable number.

81531484 is a deficient number, since it is larger than the sum of its proper divisors (61290524).

81531484 is a wasteful number, since it uses less digits than its factorization.

81531484 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20276 (or 20274 counting only the distinct ones).

The product of its digits is 15360, while the sum is 34.

The square root of 81531484 is about 9029.4786117472. The cubic root of 81531484 is about 433.6191453060.

The spelling of 81531484 in words is "eighty-one million, five hundred thirty-one thousand, four hundred eighty-four".