18409988 has 12 divisors (see below), whose sum is σ = 32363520. Its totient is φ = 9163272.

The previous prime is 18409987. The next prime is 18410003. The reversal of 18409988 is 88990481.

It is not an unprimeable number, because it can be changed into a prime (18409987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9428 + ... + 11211.

It is an arithmetic number, because the mean of its divisors is an integer number (2696960).

Almost surely, 2^18409988 is an apocalyptic number.

It is an amenable number.

18409988 is a deficient number, since it is larger than the sum of its proper divisors (13953532).

18409988 is a wasteful number, since it uses less digits than its factorization.

18409988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20866 (or 20864 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 47.

The square root of 18409988 is about 4290.6861922075. The cubic root of 18409988 is about 264.0489846356.

The spelling of 18409988 in words is "eighteen million, four hundred nine thousand, nine hundred eighty-eight".