19986918 has 16 divisors (see below), whose sum is σ = 45684480. Its totient is φ = 5710536.

The previous prime is 19986893. The next prime is 19986929. The reversal of 19986918 is 81968991.

It is a happy number.

It is a super-2 number, since 2×19986918² = 798953782277448, which contains 22 as substring.

It is a congruent number.

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, 237898 + ... + 237981.

It is an arithmetic number, because the mean of its divisors is an integer number (2855280).

Almost surely, 2^19986918 is an apocalyptic number.

19986918 is an abundant number, since it is smaller than the sum of its proper divisors (25697562).

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

19986918 is a wasteful number, since it uses less digits than its factorization.

19986918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 475891.

The product of its digits is 279936, while the sum is 51.

The square root of 19986918 is about 4470.6731036836. The cubic root of 19986918 is about 271.3825653988.

The spelling of 19986918 in words is "nineteen million, nine hundred eighty-six thousand, nine hundred eighteen".