18237220 has 12 divisors (see below), whose sum is σ = 38298204. Its totient is φ = 7294880.

The previous prime is 18237211. The next prime is 18237221. The reversal of 18237220 is 2273281.

It can be written as a sum of positive squares in 2 ways, for example, as 11235904 + 7001316 = 3352^2 + 2646^2 .

It is not an unprimeable number, because it can be changed into a prime (18237221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 455911 + ... + 455950.

It is an arithmetic number, because the mean of its divisors is an integer number (3191517).

Almost surely, 2^18237220 is an apocalyptic number.

18237220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18237220 is an abundant number, since it is smaller than the sum of its proper divisors (20060984).

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

18237220 is a wasteful number, since it uses less digits than its factorization.

18237220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 911870 (or 911868 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 18237220 is about 4270.5058248409. The cubic root of 18237220 is about 263.2204005769.

The spelling of 18237220 in words is "eighteen million, two hundred thirty-seven thousand, two hundred twenty".