81253479 has 4 divisors (see below), whose sum is σ = 108337976. Its totient is φ = 54168984.

The previous prime is 81253477. The next prime is 81253493. The reversal of 81253479 is 97435218.

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

It is not a de Polignac number, because 81253479 - 2¹ = 81253477 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 (81253477) 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, 13542244 + ... + 13542249.

It is an arithmetic number, because the mean of its divisors is an integer number (27084494).

Almost surely, 2^81253479 is an apocalyptic number.

81253479 is a deficient number, since it is larger than the sum of its proper divisors (27084497).

81253479 is a wasteful number, since it uses less digits than its factorization.

81253479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27084496.

The product of its digits is 60480, while the sum is 39.

The square root of 81253479 is about 9014.0711667925. The cubic root of 81253479 is about 433.1257344199.

The spelling of 81253479 in words is "eighty-one million, two hundred fifty-three thousand, four hundred seventy-nine".