18465221 has 2 divisors, whose sum is σ = 18465222. Its totient is φ = 18465220.

The previous prime is 18465203. The next prime is 18465233. The reversal of 18465221 is 12256481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12285025 + 6180196 = 3505^2 + 2486^2 .

It is a cyclic number.

It is not a de Polignac number, because 18465221 - 2⁶ = 18465157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18465121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9232610 + 9232611.

It is an arithmetic number, because the mean of its divisors is an integer number (9232611).

Almost surely, 2^18465221 is an apocalyptic number.

It is an amenable number.

18465221 is a deficient number, since it is larger than the sum of its proper divisors (1).

18465221 is an equidigital number, since it uses as much as digits as its factorization.

18465221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3840, while the sum is 29.

The square root of 18465221 is about 4297.1177549609. The cubic root of 18465221 is about 264.3127844963.

The spelling of 18465221 in words is "eighteen million, four hundred sixty-five thousand, two hundred twenty-one".