18059221 has 2 divisors, whose sum is σ = 18059222. Its totient is φ = 18059220.

The previous prime is 18059207. The next prime is 18059243. The reversal of 18059221 is 12295081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16924996 + 1134225 = 4114^2 + 1065^2 .

It is an emirp because it is prime and its reverse (12295081) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18059221 - 2⁵ = 18059189 is a prime.

It is a super-2 number, since 2×18059221² = 652270926253682, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18059221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18059201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9029610 + 9029611.

It is an arithmetic number, because the mean of its divisors is an integer number (9029611).

Almost surely, 2^18059221 is an apocalyptic number.

It is an amenable number.

18059221 is a deficient number, since it is larger than the sum of its proper divisors (1).

18059221 is an equidigital number, since it uses as much as digits as its factorization.

18059221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 18059221 is about 4249.6142177850. The cubic root of 18059221 is about 262.3612376205.

It can be divided in two parts, 1805 and 9221, that added together give a triangular number (11026 = T₁₄₈).

The spelling of 18059221 in words is "eighteen million, fifty-nine thousand, two hundred twenty-one".