20979617 has 4 divisors (see below), whose sum is σ = 21073920. Its totient is φ = 20885316.

The previous prime is 20979613. The next prime is 20979641. The reversal of 20979617 is 71697902.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 71697902 = 2 ⋅35848951.

It is a cyclic number.

It is not a de Polignac number, because 20979617 - 2² = 20979613 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20979613) 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, 46817 + ... + 47262.

It is an arithmetic number, because the mean of its divisors is an integer number (5268480).

Almost surely, 2^20979617 is an apocalyptic number.

It is an amenable number.

20979617 is a deficient number, since it is larger than the sum of its proper divisors (94303).

20979617 is an equidigital number, since it uses as much as digits as its factorization.

20979617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94302.

The product of its (nonzero) digits is 47628, while the sum is 41.

The square root of 20979617 is about 4580.3511874091. The cubic root of 20979617 is about 275.8031265975.

The spelling of 20979617 in words is "twenty million, nine hundred seventy-nine thousand, six hundred seventeen".