81131859239 has 2 divisors, whose sum is σ = 81131859240. Its totient is φ = 81131859238.

The previous prime is 81131859229. The next prime is 81131859293. The reversal of 81131859239 is 93295813118.

Together with next prime (81131859293) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81131859239 - 2⁴ = 81131859223 is a prime.

It is a super-3 number, since 3×81131859239³ (a number of 34 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81131859229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40565929619 + 40565929620.

It is an arithmetic number, because the mean of its divisors is an integer number (40565929620).

Almost surely, 2^81131859239 is an apocalyptic number.

81131859239 is a deficient number, since it is larger than the sum of its proper divisors (1).

81131859239 is an equidigital number, since it uses as much as digits as its factorization.

81131859239 is an evil number, because the sum of its binary digits is even.

The product of its digits is 466560, while the sum is 50.

The spelling of 81131859239 in words is "eighty-one billion, one hundred thirty-one million, eight hundred fifty-nine thousand, two hundred thirty-nine".