22566221 has 2 divisors, whose sum is σ = 22566222. Its totient is φ = 22566220.

The previous prime is 22566163. The next prime is 22566223. The reversal of 22566221 is 12266522.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22562500 + 3721 = 4750^2 + 61^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-22566221 is a prime.

It is a Sophie Germain prime.

Together with 22566223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22566223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11283110 + 11283111.

It is an arithmetic number, because the mean of its divisors is an integer number (11283111).

Almost surely, 2^22566221 is an apocalyptic number.

It is an amenable number.

22566221 is a deficient number, since it is larger than the sum of its proper divisors (1).

22566221 is an equidigital number, since it uses as much as digits as its factorization.

22566221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 26.

The square root of 22566221 is about 4750.3916680628. The cubic root of 22566221 is about 282.5874989357.

The spelling of 22566221 in words is "twenty-two million, five hundred sixty-six thousand, two hundred twenty-one".