22555721 has 2 divisors, whose sum is σ = 22555722. Its totient is φ = 22555720.

The previous prime is 22555703. The next prime is 22555727. The reversal of 22555721 is 12755522.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22429696 + 126025 = 4736^2 + 355^2 .

It is a cyclic number.

It is not a de Polignac number, because 22555721 - 2¹⁸ = 22293577 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (22555727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11277860 + 11277861.

It is an arithmetic number, because the mean of its divisors is an integer number (11277861).

Almost surely, 2^22555721 is an apocalyptic number.

It is an amenable number.

22555721 is a deficient number, since it is larger than the sum of its proper divisors (1).

22555721 is an equidigital number, since it uses as much as digits as its factorization.

22555721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7000, while the sum is 29.

The square root of 22555721 is about 4749.2863674451. The cubic root of 22555721 is about 282.5436630765.

The spelling of 22555721 in words is "twenty-two million, five hundred fifty-five thousand, seven hundred twenty-one".