20994979 has 2 divisors, whose sum is σ = 20994980. Its totient is φ = 20994978.

The previous prime is 20994959. The next prime is 20994989. The reversal of 20994979 is 97949902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20994979 - 2⁷ = 20994851 is a prime.

It is not a weakly prime, because it can be changed into another prime (20994959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10497489 + 10497490.

It is an arithmetic number, because the mean of its divisors is an integer number (10497490).

Almost surely, 2^20994979 is an apocalyptic number.

20994979 is a deficient number, since it is larger than the sum of its proper divisors (1).

20994979 is an equidigital number, since it uses as much as digits as its factorization.

20994979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 367416, while the sum is 49.

The square root of 20994979 is about 4582.0278261922. The cubic root of 20994979 is about 275.8704276977.

The spelling of 20994979 in words is "twenty million, nine hundred ninety-four thousand, nine hundred seventy-nine".