222221921 has 2 divisors, whose sum is σ = 222221922. Its totient is φ = 222221920.

The previous prime is 222221869. The next prime is 222221939. The reversal of 222221921 is 129122222.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 121440400 + 100781521 = 11020^2 + 10039^2 .

It is a cyclic number.

It is not a de Polignac number, because 222221921 - 2¹⁴ = 222205537 is a prime.

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 (222221971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 111110960 + 111110961.

It is an arithmetic number, because the mean of its divisors is an integer number (111110961).

Almost surely, 2^222221921 is an apocalyptic number.

It is an amenable number.

222221921 is a deficient number, since it is larger than the sum of its proper divisors (1).

222221921 is an equidigital number, since it uses as much as digits as its factorization.

222221921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 23.

The square root of 222221921 is about 14907.1097466947. The cubic root of 222221921 is about 605.7065905987.

The spelling of 222221921 in words is "two hundred twenty-two million, two hundred twenty-one thousand, nine hundred twenty-one".