20979131 has 4 divisors (see below), whose sum is σ = 21130200. Its totient is φ = 20828064.

The previous prime is 20979109. The next prime is 20979137. The reversal of 20979131 is 13197902.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13197902 = 2 ⋅6598951.

It is a cyclic number.

It is not a de Polignac number, because 20979131 - 2⁶ = 20979067 is a prime.

It is a super-2 number, since 2×20979131² = 880247875030322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20979137) 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, 75326 + ... + 75603.

It is an arithmetic number, because the mean of its divisors is an integer number (5282550).

Almost surely, 2^20979131 is an apocalyptic number.

20979131 is a deficient number, since it is larger than the sum of its proper divisors (151069).

20979131 is a wasteful number, since it uses less digits than its factorization.

20979131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151068.

The product of its (nonzero) digits is 3402, while the sum is 32.

The square root of 20979131 is about 4580.2981344013. The cubic root of 20979131 is about 275.8009968898.

The spelling of 20979131 in words is "twenty million, nine hundred seventy-nine thousand, one hundred thirty-one".