18228149 has 4 divisors (see below), whose sum is σ = 18672780. Its totient is φ = 17783520.

The previous prime is 18228083. The next prime is 18228157. The reversal of 18228149 is 94182281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 94182281 = 71 ⋅1326511.

It can be written as a sum of positive squares in 2 ways, for example, as 1768900 + 16459249 = 1330^2 + 4057^2 .

It is a cyclic number.

It is not a de Polignac number, because 18228149 - 2¹² = 18224053 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18228349) 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, 222254 + ... + 222335.

It is an arithmetic number, because the mean of its divisors is an integer number (4668195).

Almost surely, 2^18228149 is an apocalyptic number.

It is an amenable number.

18228149 is a deficient number, since it is larger than the sum of its proper divisors (444631).

18228149 is an equidigital number, since it uses as much as digits as its factorization.

18228149 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 444630.

The product of its digits is 9216, while the sum is 35.

The square root of 18228149 is about 4269.4436405696. The cubic root of 18228149 is about 263.1767523265.

The spelling of 18228149 in words is "eighteen million, two hundred twenty-eight thousand, one hundred forty-nine".