18019988 has 24 divisors (see below), whose sum is σ = 36809472. Its totient is φ = 7557984.

The previous prime is 18019943. The next prime is 18019993. The reversal of 18019988 is 88991081.

It is a happy number.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors.

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, 5531 + ... + 8162.

It is an arithmetic number, because the mean of its divisors is an integer number (1533728).

Almost surely, 2^18019988 is an apocalyptic number.

It is an amenable number.

18019988 is an abundant number, since it is smaller than the sum of its proper divisors (18789484).

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

18019988 is a wasteful number, since it uses less digits than its factorization.

18019988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13751 (or 13749 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 44.

The square root of 18019988 is about 4244.9956419294. The cubic root of 18019988 is about 262.1711097937.

The spelling of 18019988 in words is "eighteen million, nineteen thousand, nine hundred eighty-eight".