18556990 has 16 divisors (see below), whose sum is σ = 33902352. Its totient is φ = 7311744.

The previous prime is 18556981. The next prime is 18556991. The reversal of 18556990 is 9965581.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18556991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13179 + ... + 14518.

It is an arithmetic number, because the mean of its divisors is an integer number (2118897).

Almost surely, 2^18556990 is an apocalyptic number.

18556990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18556990 is a deficient number, since it is larger than the sum of its proper divisors (15345362).

18556990 is a wasteful number, since it uses less digits than its factorization.

18556990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27771.

The product of its (nonzero) digits is 97200, while the sum is 43.

The square root of 18556990 is about 4307.7824921878. The cubic root of 18556990 is about 264.7499242816.

It can be divided in two parts, 185 and 56990, that added together give a palindrome (57175).

The spelling of 18556990 in words is "eighteen million, five hundred fifty-six thousand, nine hundred ninety".