22218509 has 2 divisors, whose sum is σ = 22218510. Its totient is φ = 22218508.

The previous prime is 22218419. The next prime is 22218551. The reversal of 22218509 is 90581222.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21362884 + 855625 = 4622^2 + 925^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-22218509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22218569) 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, 11109254 + 11109255.

It is an arithmetic number, because the mean of its divisors is an integer number (11109255).

Almost surely, 2^22218509 is an apocalyptic number.

It is an amenable number.

22218509 is a deficient number, since it is larger than the sum of its proper divisors (1).

22218509 is an equidigital number, since it uses as much as digits as its factorization.

22218509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 22218509 is about 4713.6513447645. The cubic root of 22218509 is about 281.1285616304.

The spelling of 22218509 in words is "twenty-two million, two hundred eighteen thousand, five hundred nine".