81979743259 has 4 divisors (see below), whose sum is σ = 81981659704. Its totient is φ = 81977826816.

The previous prime is 81979743247. The next prime is 81979743283. The reversal of 81979743259 is 95234797918.

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

It is a cyclic number.

It is not a de Polignac number, because 81979743259 - 2⁵ = 81979743227 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 81979743259.

It is not an unprimeable number, because it can be changed into a prime (81979743239) 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, 892557 + ... + 980110.

It is an arithmetic number, because the mean of its divisors is an integer number (20495414926).

Almost surely, 2^81979743259 is an apocalyptic number.

81979743259 is a deficient number, since it is larger than the sum of its proper divisors (1916445).

81979743259 is a wasteful number, since it uses less digits than its factorization.

81979743259 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1916444.

The product of its digits is 34292160, while the sum is 64.

The spelling of 81979743259 in words is "eighty-one billion, nine hundred seventy-nine million, seven hundred forty-three thousand, two hundred fifty-nine".