18306220 has 12 divisors (see below), whose sum is σ = 38443104. Its totient is φ = 7322480.

The previous prime is 18306217. The next prime is 18306247. The reversal of 18306220 is 2260381.

It is a junction number, because it is equal to n+sod(n) for n = 18306191 and 18306200.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 457636 + ... + 457675.

It is an arithmetic number, because the mean of its divisors is an integer number (3203592).

Almost surely, 2^18306220 is an apocalyptic number.

18306220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18306220 is an abundant number, since it is smaller than the sum of its proper divisors (20136884).

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

18306220 is a wasteful number, since it uses less digits than its factorization.

18306220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 915320 (or 915318 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 18306220 is about 4278.5768662021. The cubic root of 18306220 is about 263.5519450825.

The spelling of 18306220 in words is "eighteen million, three hundred six thousand, two hundred twenty".