81137958919 has 2 divisors, whose sum is σ = 81137958920. Its totient is φ = 81137958918.

The previous prime is 81137958917. The next prime is 81137958931. The reversal of 81137958919 is 91985973118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81137958919 - 2¹ = 81137958917 is a prime.

It is a super-2 number, since 2×81137958919² (a number of 23 digits) contains 22 as substring.

Together with 81137958917, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81137958917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40568979459 + 40568979460.

It is an arithmetic number, because the mean of its divisors is an integer number (40568979460).

Almost surely, 2^81137958919 is an apocalyptic number.

81137958919 is a deficient number, since it is larger than the sum of its proper divisors (1).

81137958919 is an equidigital number, since it uses as much as digits as its factorization.

81137958919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4898880, while the sum is 61.

The spelling of 81137958919 in words is "eighty-one billion, one hundred thirty-seven million, nine hundred fifty-eight thousand, nine hundred nineteen".