20980979 has 4 divisors (see below), whose sum is σ = 20992200. Its totient is φ = 20969760.

The previous prime is 20980957. The next prime is 20980987. The reversal of 20980979 is 97908902.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20980979 - 2⁸ = 20980723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20980919) 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, 2054 + ... + 6795.

It is an arithmetic number, because the mean of its divisors is an integer number (5248050).

Almost surely, 2^20980979 is an apocalyptic number.

20980979 is a deficient number, since it is larger than the sum of its proper divisors (11221).

20980979 is an equidigital number, since it uses as much as digits as its factorization.

20980979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11220.

The product of its (nonzero) digits is 81648, while the sum is 44.

The square root of 20980979 is about 4580.4998635520. The cubic root of 20980979 is about 275.8090948623.

The spelling of 20980979 in words is "twenty million, nine hundred eighty thousand, nine hundred seventy-nine".