81697988612239 has 2 divisors, whose sum is σ = 81697988612240. Its totient is φ = 81697988612238.

The previous prime is 81697988612189. The next prime is 81697988612243. The reversal of 81697988612239 is 93221688979618.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81697988612239 - 2²⁹ = 81697451741327 is a prime.

It is a super-2 number, since 2×81697988612239² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81697988612299) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40848994306119 + 40848994306120.

It is an arithmetic number, because the mean of its divisors is an integer number (40848994306120).

Almost surely, 2^{81697988612239} is an apocalyptic number.

81697988612239 is a deficient number, since it is larger than the sum of its proper divisors (1).

81697988612239 is an equidigital number, since it uses as much as digits as its factorization.

81697988612239 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1128701952, while the sum is 79.

The spelling of 81697988612239 in words is "eighty-one trillion, six hundred ninety-seven billion, nine hundred eighty-eight million, six hundred twelve thousand, two hundred thirty-nine".