18248221 has 4 divisors (see below), whose sum is σ = 18877500. Its totient is φ = 17618944.

The previous prime is 18248183. The next prime is 18248231. The reversal of 18248221 is 12284281.

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 15405625 + 2842596 = 3925^2 + 1686^2 .

It is a cyclic number.

It is not a de Polignac number, because 18248221 - 2⁷ = 18248093 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18248221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18248231) 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, 314596 + ... + 314653.

It is an arithmetic number, because the mean of its divisors is an integer number (4719375).

Almost surely, 2^18248221 is an apocalyptic number.

It is an amenable number.

18248221 is a deficient number, since it is larger than the sum of its proper divisors (629279).

18248221 is an equidigital number, since it uses as much as digits as its factorization.

18248221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 629278.

The product of its digits is 2048, while the sum is 28.

The square root of 18248221 is about 4271.7936513835. The cubic root of 18248221 is about 263.2733162731.

The spelling of 18248221 in words is "eighteen million, two hundred forty-eight thousand, two hundred twenty-one".