18661100 has 36 divisors (see below), whose sum is σ = 40757808. Its totient is φ = 7416000.

The previous prime is 18661099. The next prime is 18661129. The reversal of 18661100 is 116681.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17585 + ... + 18615.

Almost surely, 2^18661100 is an apocalyptic number.

18661100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18661100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20378904).

18661100 is an abundant number, since it is smaller than the sum of its proper divisors (22096708).

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

18661100 is a wasteful number, since it uses less digits than its factorization.

18661100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1226 (or 1219 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 18661100 is about 4319.8495344167. The cubic root of 18661100 is about 265.2441087558.

Adding to 18661100 its reverse (116681), we get a palindrome (18777781).

The spelling of 18661100 in words is "eighteen million, six hundred sixty-one thousand, one hundred".