81518871367 has 4 divisors (see below), whose sum is σ = 81806924200. Its totient is φ = 81230818536.

The previous prime is 81518871323. The next prime is 81518871383. The reversal of 81518871367 is 76317881518.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81518871367 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 (81518871397) 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, 144025992 + ... + 144026557.

It is an arithmetic number, because the mean of its divisors is an integer number (20451731050).

Almost surely, 2^81518871367 is an apocalyptic number.

81518871367 is a deficient number, since it is larger than the sum of its proper divisors (288052833).

81518871367 is a wasteful number, since it uses less digits than its factorization.

81518871367 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288052832.

The product of its digits is 2257920, while the sum is 55.

The spelling of 81518871367 in words is "eighty-one billion, five hundred eighteen million, eight hundred seventy-one thousand, three hundred sixty-seven".