79581639 has 4 divisors (see below), whose sum is σ = 106108856. Its totient is φ = 53054424.

The previous prime is 79581617. The next prime is 79581643. The reversal of 79581639 is 93618597.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93618597 = 3 ⋅31206199.

It is not a de Polignac number, because 79581639 - 2¹² = 79577543 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 (79581659) 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, 13263604 + ... + 13263609.

It is an arithmetic number, because the mean of its divisors is an integer number (26527214).

Almost surely, 2^79581639 is an apocalyptic number.

79581639 is a deficient number, since it is larger than the sum of its proper divisors (26527217).

79581639 is a wasteful number, since it uses less digits than its factorization.

79581639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26527216.

The product of its digits is 408240, while the sum is 48.

The square root of 79581639 is about 8920.8541631393. The cubic root of 79581639 is about 430.1345153341.

The spelling of 79581639 in words is "seventy-nine million, five hundred eighty-one thousand, six hundred thirty-nine".