18381229 has 2 divisors, whose sum is σ = 18381230. Its totient is φ = 18381228.

The previous prime is 18381217. The next prime is 18381239. The reversal of 18381229 is 92218381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10530025 + 7851204 = 3245^2 + 2802^2 .

It is a cyclic number.

It is not a de Polignac number, because 18381229 - 2⁵ = 18381197 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18381194 and 18381203.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18381239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9190614 + 9190615.

It is an arithmetic number, because the mean of its divisors is an integer number (9190615).

Almost surely, 2^18381229 is an apocalyptic number.

It is an amenable number.

18381229 is a deficient number, since it is larger than the sum of its proper divisors (1).

18381229 is an equidigital number, since it uses as much as digits as its factorization.

18381229 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 34.

The square root of 18381229 is about 4287.3335536205. Note that the first 3 decimals coincide. The cubic root of 18381229 is about 263.9114190494.

The spelling of 18381229 in words is "eighteen million, three hundred eighty-one thousand, two hundred twenty-nine".