21122291 has 2 divisors, whose sum is σ = 21122292. Its totient is φ = 21122290.

The previous prime is 21122267. The next prime is 21122323. The reversal of 21122291 is 19222112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21122291 - 2¹⁴ = 21105907 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21122201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561145 + 10561146.

It is an arithmetic number, because the mean of its divisors is an integer number (10561146).

Almost surely, 2^21122291 is an apocalyptic number.

21122291 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122291 is an equidigital number, since it uses as much as digits as its factorization.

21122291 is an evil number, because the sum of its binary digits is even.

The product of its digits is 144, while the sum is 20.

The square root of 21122291 is about 4595.8993679148. The cubic root of 21122291 is about 276.4269236494.

The spelling of 21122291 in words is "twenty-one million, one hundred twenty-two thousand, two hundred ninety-one".