19998169 has 2 divisors, whose sum is σ = 19998170. Its totient is φ = 19998168.

The previous prime is 19998163. The next prime is 19998217. The reversal of 19998169 is 96189991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11471769 + 8526400 = 3387^2 + 2920^2 .

It is an emirp because it is prime and its reverse (96189991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19998169 - 2³ = 19998161 is a prime.

It is a super-2 number, since 2×19998169² = 799853526705122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (19998161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999084 + 9999085.

It is an arithmetic number, because the mean of its divisors is an integer number (9999085).

Almost surely, 2^19998169 is an apocalyptic number.

It is an amenable number.

19998169 is a deficient number, since it is larger than the sum of its proper divisors (1).

19998169 is an equidigital number, since it uses as much as digits as its factorization.

19998169 is an evil number, because the sum of its binary digits is even.

The product of its digits is 314928, while the sum is 52.

The square root of 19998169 is about 4471.9312382907. The cubic root of 19998169 is about 271.4334779089.

The spelling of 19998169 in words is "nineteen million, nine hundred ninety-eight thousand, one hundred sixty-nine".