18500220 has 72 divisors (see below), whose sum is σ = 56871360. Its totient is φ = 4867200.

The previous prime is 18500219. The next prime is 18500221. The reversal of 18500220 is 2200581.

It is an interprime number because it is at equal distance from previous prime (18500219) and next prime (18500221).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 18500193 and 18500202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18500221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13570 + ... + 14870.

It is an arithmetic number, because the mean of its divisors is an integer number (789880).

Almost surely, 2^18500220 is an apocalyptic number.

18500220 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 18500220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28435680).

18500220 is an abundant number, since it is smaller than the sum of its proper divisors (38371140).

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

18500220 is a wasteful number, since it uses less digits than its factorization.

18500220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1395 (or 1390 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 18500220 is about 4301.1882079258. The cubic root of 18500220 is about 264.4796720143.

The spelling of 18500220 in words is "eighteen million, five hundred thousand, two hundred twenty".