81729266099531 has 2 divisors, whose sum is σ = 81729266099532. Its totient is φ = 81729266099530.

The previous prime is 81729266099501. The next prime is 81729266099597. The reversal of 81729266099531 is 13599066292718.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81729266099531 - 2²² = 81729261905227 is a prime.

It is a super-2 number, since 2×81729266099531² (a number of 29 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81729266099501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40864633049765 + 40864633049766.

It is an arithmetic number, because the mean of its divisors is an integer number (40864633049766).

Almost surely, 2^{81729266099531} is an apocalyptic number.

81729266099531 is a deficient number, since it is larger than the sum of its proper divisors (1).

81729266099531 is an equidigital number, since it uses as much as digits as its factorization.

81729266099531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 88179840, while the sum is 68.

The spelling of 81729266099531 in words is "eighty-one trillion, seven hundred twenty-nine billion, two hundred sixty-six million, ninety-nine thousand, five hundred thirty-one".