20939579 has 4 divisors (see below), whose sum is σ = 21135384. Its totient is φ = 20743776.

The previous prime is 20939557. The next prime is 20939593. The reversal of 20939579 is 97593902.

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 20939579 - 2²⁴ = 4162363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20939519) 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, 97742 + ... + 97955.

It is an arithmetic number, because the mean of its divisors is an integer number (5283846).

Almost surely, 2^20939579 is an apocalyptic number.

20939579 is a deficient number, since it is larger than the sum of its proper divisors (195805).

20939579 is a wasteful number, since it uses less digits than its factorization.

20939579 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195804.

The product of its (nonzero) digits is 153090, while the sum is 44.

The square root of 20939579 is about 4575.9784745997. The cubic root of 20939579 is about 275.6275651196.

The spelling of 20939579 in words is "twenty million, nine hundred thirty-nine thousand, five hundred seventy-nine".