81231116479 has 4 divisors (see below), whose sum is σ = 84762904176. Its totient is φ = 77699328784.

The previous prime is 81231116471. The next prime is 81231116489. The reversal of 81231116479 is 97461113218.

It is a happy number.

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 81231116479 - 2³ = 81231116471 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 (81231116471) 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, 1765893814 + ... + 1765893859.

It is an arithmetic number, because the mean of its divisors is an integer number (21190726044).

Almost surely, 2^81231116479 is an apocalyptic number.

81231116479 is a deficient number, since it is larger than the sum of its proper divisors (3531787697).

81231116479 is a wasteful number, since it uses less digits than its factorization.

81231116479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3531787696.

The product of its digits is 72576, while the sum is 43.

The spelling of 81231116479 in words is "eighty-one billion, two hundred thirty-one million, one hundred sixteen thousand, four hundred seventy-nine".