81579193 has 4 divisors (see below), whose sum is σ = 82371328. Its totient is φ = 80787060.

The previous prime is 81579151. The next prime is 81579221. The reversal of 81579193 is 39197518.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81579193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81579493) 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, 395913 + ... + 396118.

It is an arithmetic number, because the mean of its divisors is an integer number (20592832).

Almost surely, 2^81579193 is an apocalyptic number.

It is an amenable number.

81579193 is a deficient number, since it is larger than the sum of its proper divisors (792135).

81579193 is a wasteful number, since it uses less digits than its factorization.

81579193 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 792134.

The product of its digits is 68040, while the sum is 43.

The square root of 81579193 is about 9032.1200722754. The cubic root of 81579193 is about 433.7037077389.

It can be divided in two parts, 815 and 79193, that added together give a palindrome (80008).

The spelling of 81579193 in words is "eighty-one million, five hundred seventy-nine thousand, one hundred ninety-three".