20958979 has 2 divisors, whose sum is σ = 20958980. Its totient is φ = 20958978.

The previous prime is 20958961. The next prime is 20958989. The reversal of 20958979 is 97985902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20958979 - 2¹¹ = 20956931 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20958989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10479489 + 10479490.

It is an arithmetic number, because the mean of its divisors is an integer number (10479490).

Almost surely, 2^20958979 is an apocalyptic number.

20958979 is a deficient number, since it is larger than the sum of its proper divisors (1).

20958979 is an equidigital number, since it uses as much as digits as its factorization.

20958979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 408240, while the sum is 49.

The square root of 20958979 is about 4578.0977490657. The cubic root of 20958979 is about 275.7126595441.

The spelling of 20958979 in words is "twenty million, nine hundred fifty-eight thousand, nine hundred seventy-nine".