21122399 has 2 divisors, whose sum is σ = 21122400. Its totient is φ = 21122398.

The previous prime is 21122393. The next prime is 21122419. The reversal of 21122399 is 99322112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21122399 - 2⁴ = 21122383 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21122393) 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, 10561199 + 10561200.

It is an arithmetic number, because the mean of its divisors is an integer number (10561200).

Almost surely, 2^21122399 is an apocalyptic number.

21122399 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122399 is an equidigital number, since it uses as much as digits as its factorization.

21122399 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944, while the sum is 29.

The square root of 21122399 is about 4595.9111175043. The cubic root of 21122399 is about 276.4273947798.

The spelling of 21122399 in words is "twenty-one million, one hundred twenty-two thousand, three hundred ninety-nine".