18400090 has 16 divisors (see below), whose sum is σ = 33215688. Its totient is φ = 7338816.

The previous prime is 18400073. The next prime is 18400091. The reversal of 18400090 is 9000481.

It can be written as a sum of positive squares in 4 ways, for example, as 13564489 + 4835601 = 3683^2 + 2199^2 .

It is not an unprimeable number, because it can be changed into a prime (18400091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1264 + ... + 6196.

Almost surely, 2^18400090 is an apocalyptic number.

18400090 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18400090 is a deficient number, since it is larger than the sum of its proper divisors (14815598).

18400090 is a wasteful number, since it uses less digits than its factorization.

18400090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5313.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 18400090 is about 4289.5326085717. The cubic root of 18400090 is about 264.0016547953.

The spelling of 18400090 in words is "eighteen million, four hundred thousand, ninety".