81692581157389 has 4 divisors (see below), whose sum is σ = 82240853514300. Its totient is φ = 81144308800480.

The previous prime is 81692581157329. The next prime is 81692581157423. The reversal of 81692581157389 is 98375118529618.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 43559115604489 + 38133465552900 = 6599933^2 + 6175230^2 .

It is a cyclic number.

It is not a de Polignac number, because 81692581157389 - 2²⁹ = 81692044286477 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81692581157309) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 274136178232 + ... + 274136178529.

It is an arithmetic number, because the mean of its divisors is an integer number (20560213378575).

Almost surely, 2^{81692581157389} is an apocalyptic number.

It is an amenable number.

81692581157389 is a deficient number, since it is larger than the sum of its proper divisors (548272356911).

81692581157389 is a wasteful number, since it uses less digits than its factorization.

81692581157389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 548272356910.

The product of its digits is 261273600, while the sum is 73.

The spelling of 81692581157389 in words is "eighty-one trillion, six hundred ninety-two billion, five hundred eighty-one million, one hundred fifty-seven thousand, three hundred eighty-nine".