81137738879 has 2 divisors, whose sum is σ = 81137738880. Its totient is φ = 81137738878.

The previous prime is 81137738777. The next prime is 81137738897. The reversal of 81137738879 is 97883773118.

It is a happy number.

Together with next prime (81137738897) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81137738879 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81137738179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40568869439 + 40568869440.

It is an arithmetic number, because the mean of its divisors is an integer number (40568869440).

Almost surely, 2^81137738879 is an apocalyptic number.

81137738879 is a deficient number, since it is larger than the sum of its proper divisors (1).

81137738879 is an equidigital number, since it uses as much as digits as its factorization.

81137738879 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14224896, while the sum is 62.

The spelling of 81137738879 in words is "eighty-one billion, one hundred thirty-seven million, seven hundred thirty-eight thousand, eight hundred seventy-nine".