81239493 has 16 divisors (see below), whose sum is σ = 109892160. Its totient is φ = 53379456.

The previous prime is 81239489. The next prime is 81239503. The reversal of 81239493 is 39493218.

It is not a de Polignac number, because 81239493 - 2² = 81239489 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81239423) 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, 63898 + ... + 65156.

It is an arithmetic number, because the mean of its divisors is an integer number (6868260).

Almost surely, 2^81239493 is an apocalyptic number.

It is an amenable number.

81239493 is a deficient number, since it is larger than the sum of its proper divisors (28652667).

81239493 is a wasteful number, since it uses less digits than its factorization.

81239493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1556.

The product of its digits is 46656, while the sum is 39.

The square root of 81239493 is about 9013.2953463203. The cubic root of 81239493 is about 433.1008819697.

The spelling of 81239493 in words is "eighty-one million, two hundred thirty-nine thousand, four hundred ninety-three".