19998138 has 16 divisors (see below), whose sum is σ = 40262976. Its totient is φ = 6621600.

The previous prime is 19998047. The next prime is 19998149. The reversal of 19998138 is 83189991.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10131 + ... + 11942.

It is an arithmetic number, because the mean of its divisors is an integer number (2516436).

Almost surely, 2^19998138 is an apocalyptic number.

19998138 is an abundant number, since it is smaller than the sum of its proper divisors (20264838).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19998138 is a wasteful number, since it uses less digits than its factorization.

19998138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22229.

The product of its digits is 139968, while the sum is 48.

The square root of 19998138 is about 4471.9277722253. The cubic root of 19998138 is about 271.4333376554.

The spelling of 19998138 in words is "nineteen million, nine hundred ninety-eight thousand, one hundred thirty-eight".