19804979 has 2 divisors, whose sum is σ = 19804980. Its totient is φ = 19804978.

The previous prime is 19804969. The next prime is 19804991. The reversal of 19804979 is 97940891.

It is a weak prime.

It is an emirp because it is prime and its reverse (97940891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19804979 - 2²⁴ = 3027763 is a prime.

It is not a weakly prime, because it can be changed into another prime (19804969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9902489 + 9902490.

It is an arithmetic number, because the mean of its divisors is an integer number (9902490).

Almost surely, 2^19804979 is an apocalyptic number.

19804979 is a deficient number, since it is larger than the sum of its proper divisors (1).

19804979 is an equidigital number, since it uses as much as digits as its factorization.

19804979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 163296, while the sum is 47.

The square root of 19804979 is about 4450.2785306091. The cubic root of 19804979 is about 270.5565975714.

The spelling of 19804979 in words is "nineteen million, eight hundred four thousand, nine hundred seventy-nine".