18273990 has 64 divisors (see below), whose sum is σ = 50512896. Its totient is φ = 4144512.

The previous prime is 18273979. The next prime is 18274037. The reversal of 18273990 is 9937281.

It is a Curzon number.

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 31 ways as a sum of consecutive naturals, for example, 36079 + ... + 36581.

It is an arithmetic number, because the mean of its divisors is an integer number (789264).

Almost surely, 2^18273990 is an apocalyptic number.

18273990 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 18273990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25256448).

18273990 is an abundant number, since it is smaller than the sum of its proper divisors (32238906).

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

18273990 is a wasteful number, since it uses less digits than its factorization.

18273990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 693.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 18273990 is about 4274.8087676527. The cubic root of 18273990 is about 263.3971840397.

The spelling of 18273990 in words is "eighteen million, two hundred seventy-three thousand, nine hundred ninety".