18409990 has 16 divisors (see below), whose sum is σ = 33279840. Its totient is φ = 7332480.

The previous prime is 18409987. The next prime is 18410003. The reversal of 18409990 is 9990481.

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, 1410 + ... + 6229.

It is an arithmetic number, because the mean of its divisors is an integer number (2079990).

Almost surely, 2^18409990 is an apocalyptic number.

18409990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18409990 is a deficient number, since it is larger than the sum of its proper divisors (14869850).

18409990 is a wasteful number, since it uses less digits than its factorization.

18409990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7887.

The product of its (nonzero) digits is 23328, while the sum is 40.

The square root of 18409990 is about 4290.6864252704. The cubic root of 18409990 is about 264.0489941974.

The spelling of 18409990 in words is "eighteen million, four hundred nine thousand, nine hundred ninety".