22640921 has 2 divisors, whose sum is σ = 22640922. Its totient is φ = 22640920.

The previous prime is 22640899. The next prime is 22640927. The reversal of 22640921 is 12904622.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11485321 + 11155600 = 3389^2 + 3340^2 .

It is a cyclic number.

It is not a de Polignac number, because 22640921 - 2⁶ = 22640857 is a prime.

It is a super-2 number, since 2×22640921² = 1025222607456482, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (22640927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11320460 + 11320461.

It is an arithmetic number, because the mean of its divisors is an integer number (11320461).

Almost surely, 2^22640921 is an apocalyptic number.

It is an amenable number.

22640921 is a deficient number, since it is larger than the sum of its proper divisors (1).

22640921 is an equidigital number, since it uses as much as digits as its factorization.

22640921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 22640921 is about 4758.2476816576. The cubic root of 22640921 is about 282.8989679602.

The spelling of 22640921 in words is "twenty-two million, six hundred forty thousand, nine hundred twenty-one".