19998479 has 2 divisors, whose sum is σ = 19998480. Its totient is φ = 19998478.

The previous prime is 19998427. The next prime is 19998481. The reversal of 19998479 is 97489991.

It is a strong prime.

It is an emirp because it is prime and its reverse (97489991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19998479 - 2¹⁶ = 19932943 is a prime.

It is a Sophie Germain prime.

Together with 19998481, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19998679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999239 + 9999240.

It is an arithmetic number, because the mean of its divisors is an integer number (9999240).

Almost surely, 2^19998479 is an apocalyptic number.

19998479 is a deficient number, since it is larger than the sum of its proper divisors (1).

19998479 is an equidigital number, since it uses as much as digits as its factorization.

19998479 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1469664, while the sum is 56.

The square root of 19998479 is about 4471.9658987966. The cubic root of 19998479 is about 271.4348804364.

The spelling of 19998479 in words is "nineteen million, nine hundred ninety-eight thousand, four hundred seventy-nine".