81729266009597 has 2 divisors, whose sum is σ = 81729266009598. Its totient is φ = 81729266009596.

The previous prime is 81729266009549. The next prime is 81729266009647. The reversal of 81729266009597 is 79590066292718.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 73294505010841 + 8434760998756 = 8561221^2 + 2904266^2 .

It is a cyclic number.

It is not a de Polignac number, because 81729266009597 - 2⁶ = 81729266009533 is a prime.

It is a super-2 number, since 2×81729266009597² (a number of 29 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81729266009597.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81729266000597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40864633004798 + 40864633004799.

It is an arithmetic number, because the mean of its divisors is an integer number (40864633004799).

Almost surely, 2^{81729266009597} is an apocalyptic number.

It is an amenable number.

81729266009597 is a deficient number, since it is larger than the sum of its proper divisors (1).

81729266009597 is an equidigital number, since it uses as much as digits as its factorization.

81729266009597 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 205752960, while the sum is 71.

The spelling of 81729266009597 in words is "eighty-one trillion, seven hundred twenty-nine billion, two hundred sixty-six million, nine thousand, five hundred ninety-seven".