81168442239 has 4 divisors (see below), whose sum is σ = 108224589656. Its totient is φ = 54112294824.

The previous prime is 81168442211. The next prime is 81168442259. The reversal of 81168442239 is 93224486118.

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

It is not a de Polignac number, because 81168442239 - 2¹⁷ = 81168311167 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 (81168442259) 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, 13528073704 + ... + 13528073709.

It is an arithmetic number, because the mean of its divisors is an integer number (27056147414).

Almost surely, 2^81168442239 is an apocalyptic number.

81168442239 is a deficient number, since it is larger than the sum of its proper divisors (27056147417).

81168442239 is a wasteful number, since it uses less digits than its factorization.

81168442239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27056147416.

The product of its digits is 663552, while the sum is 48.

The spelling of 81168442239 in words is "eighty-one billion, one hundred sixty-eight million, four hundred forty-two thousand, two hundred thirty-nine".