18332221 has 4 divisors (see below), whose sum is σ = 18373500. Its totient is φ = 18290944.

The previous prime is 18332213. The next prime is 18332231. The reversal of 18332221 is 12223381.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16040025 + 2292196 = 4005^2 + 1514^2 .

It is a cyclic number.

It is not a de Polignac number, because 18332221 - 2³ = 18332213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18332192 and 18332201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18332231) 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, 19966 + ... + 20863.

It is an arithmetic number, because the mean of its divisors is an integer number (4593375).

Almost surely, 2^18332221 is an apocalyptic number.

It is an amenable number.

18332221 is a deficient number, since it is larger than the sum of its proper divisors (41279).

18332221 is an equidigital number, since it uses as much as digits as its factorization.

18332221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41278.

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

The square root of 18332221 is about 4281.6142983692. The cubic root of 18332221 is about 263.6766635724.

The spelling of 18332221 in words is "eighteen million, three hundred thirty-two thousand, two hundred twenty-one".