81729618167 has 2 divisors, whose sum is σ = 81729618168. Its totient is φ = 81729618166.

The previous prime is 81729618127. The next prime is 81729618181. The reversal of 81729618167 is 76181692718.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81729618167 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81729618127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40864809083 + 40864809084.

It is an arithmetic number, because the mean of its divisors is an integer number (40864809084).

Almost surely, 2^81729618167 is an apocalyptic number.

81729618167 is a deficient number, since it is larger than the sum of its proper divisors (1).

81729618167 is an equidigital number, since it uses as much as digits as its factorization.

81729618167 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2032128, while the sum is 56.

The spelling of 81729618167 in words is "eighty-one billion, seven hundred twenty-nine million, six hundred eighteen thousand, one hundred sixty-seven".