18986220 has 144 divisors (see below), whose sum is σ = 64576512. Its totient is φ = 4475520.

The previous prime is 18986207. The next prime is 18986237. The reversal of 18986220 is 2268981.

18986220 = T₅₅ + T₅₆ + ... + T₄₈₄.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 85029 + ... + 85251.

It is an arithmetic number, because the mean of its divisors is an integer number (448448).

Almost surely, 2^18986220 is an apocalyptic number.

18986220 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 18986220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32288256).

18986220 is an abundant number, since it is smaller than the sum of its proper divisors (45590292).

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

18986220 is a wasteful number, since it uses less digits than its factorization.

18986220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 292 (or 287 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 18986220 is about 4357.3179824291. The cubic root of 18986220 is about 266.7756394902.

It can be divided in two parts, 1898 and 6220, that added together give a palindrome (8118).

The spelling of 18986220 in words is "eighteen million, nine hundred eighty-six thousand, two hundred twenty".