19998679 has 2 divisors, whose sum is σ = 19998680. Its totient is φ = 19998678.

The previous prime is 19998677. The next prime is 19998683. The reversal of 19998679 is 97689991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19998679 - 2¹ = 19998677 is a prime.

Together with 19998677, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19998677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999339 + 9999340.

It is an arithmetic number, because the mean of its divisors is an integer number (9999340).

Almost surely, 2^19998679 is an apocalyptic number.

19998679 is a deficient number, since it is larger than the sum of its proper divisors (1).

19998679 is an equidigital number, since it uses as much as digits as its factorization.

19998679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2204496, while the sum is 58.

The square root of 19998679 is about 4471.9882602708. The cubic root of 19998679 is about 271.4357852851.

The spelling of 19998679 in words is "nineteen million, nine hundred ninety-eight thousand, six hundred seventy-nine".