21422399 has 2 divisors, whose sum is σ = 21422400. Its totient is φ = 21422398.

The previous prime is 21422381. The next prime is 21422411. The reversal of 21422399 is 99322412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21422399 - 2⁸ = 21422143 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21422099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711199 + 10711200.

It is an arithmetic number, because the mean of its divisors is an integer number (10711200).

Almost surely, 2^21422399 is an apocalyptic number.

21422399 is a deficient number, since it is larger than the sum of its proper divisors (1).

21422399 is an equidigital number, since it uses as much as digits as its factorization.

21422399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 32.

The square root of 21422399 is about 4628.4337523616. The cubic root of 21422399 is about 277.7299406274.

The spelling of 21422399 in words is "twenty-one million, four hundred twenty-two thousand, three hundred ninety-nine".