81199592389 has 4 divisors (see below), whose sum is σ = 81202748256. Its totient is φ = 81196436524.

The previous prime is 81199592351. The next prime is 81199592429. The reversal of 81199592389 is 98329599118.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 98329599118 = 2 ⋅49164799559.

It is a cyclic number.

It is not a de Polignac number, because 81199592389 - 2²¹ = 81197495237 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81199592389.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81199593389) 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, 1539019 + ... + 1590904.

It is an arithmetic number, because the mean of its divisors is an integer number (20300687064).

Almost surely, 2^81199592389 is an apocalyptic number.

It is an amenable number.

81199592389 is a deficient number, since it is larger than the sum of its proper divisors (3155867).

81199592389 is a wasteful number, since it uses less digits than its factorization.

81199592389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3155866.

The product of its digits is 12597120, while the sum is 64.

The spelling of 81199592389 in words is "eighty-one billion, one hundred ninety-nine million, five hundred ninety-two thousand, three hundred eighty-nine".