20879 has 2 divisors, whose sum is σ = 20880. Its totient is φ = 20878.

The previous prime is 20873. The next prime is 20887. The reversal of 20879 is 97802.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20879 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10439 + 10440.

It is an arithmetic number, because the mean of its divisors is an integer number (10440).

2²⁰⁸⁷⁹ is an apocalyptic number.

20879 is a deficient number, since it is larger than the sum of its proper divisors (1).

20879 is an equidigital number, since it uses as much as digits as its factorization.

20879 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 20879 is about 144.4956746757. The cubic root of 20879 is about 27.5361508034.

The spelling of 20879 in words is "twenty thousand, eight hundred seventy-nine".