19998918 has 24 divisors (see below), whose sum is σ = 43597008. Its totient is φ = 6625392.

The previous prime is 19998917. The next prime is 19998943. The reversal of 19998918 is 81989991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19998917) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 321 + ... + 6332.

It is an arithmetic number, because the mean of its divisors is an integer number (1816542).

Almost surely, 2^19998918 is an apocalyptic number.

19998918 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

19998918 is an abundant number, since it is smaller than the sum of its proper divisors (23598090).

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

19998918 is a wasteful number, since it uses less digits than its factorization.

19998918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6828 (or 6825 counting only the distinct ones).

The product of its digits is 419904, while the sum is 54.

The square root of 19998918 is about 4472.0149820858. The cubic root of 19998918 is about 271.4368665714.

The spelling of 19998918 in words is "nineteen million, nine hundred ninety-eight thousand, nine hundred eighteen".