18208890 has 72 divisors (see below), whose sum is σ = 55085940. Its totient is φ = 4161024.

The previous prime is 18208889. The next prime is 18208903. The reversal of 18208890 is 9880281.

It can be written as a sum of positive squares in 2 ways, for example, as 18173169 + 35721 = 4263^2 + 189^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2346 + ... + 6474.

Almost surely, 2^18208890 is an apocalyptic number.

18208890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18208890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27542970).

18208890 is an abundant number, since it is smaller than the sum of its proper divisors (36877050).

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

18208890 is a wasteful number, since it uses less digits than its factorization.

18208890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4156 (or 4146 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

The square root of 18208890 is about 4267.1875984072. The cubic root of 18208890 is about 263.0840329620.

The spelling of 18208890 in words is "eighteen million, two hundred eight thousand, eight hundred ninety".