21422321 has 2 divisors, whose sum is σ = 21422322. Its totient is φ = 21422320.

The previous prime is 21422273. The next prime is 21422327. The reversal of 21422321 is 12322412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16516096 + 4906225 = 4064^2 + 2215^2 .

It is a cyclic number.

It is not a de Polignac number, because 21422321 - 2¹⁸ = 21160177 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21422321.

It is not a weakly prime, because it can be changed into another prime (21422327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711160 + 10711161.

It is an arithmetic number, because the mean of its divisors is an integer number (10711161).

Almost surely, 2^21422321 is an apocalyptic number.

It is an amenable number.

21422321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21422321 is an equidigital number, since it uses as much as digits as its factorization.

21422321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 192, while the sum is 17.

The square root of 21422321 is about 4628.4253261774. The cubic root of 21422321 is about 277.7296035509.

Adding to 21422321 its reverse (12322412), we get a palindrome (33744733).

Subtracting from 21422321 its reverse (12322412), we obtain a palindrome (9099909).

The spelling of 21422321 in words is "twenty-one million, four hundred twenty-two thousand, three hundred twenty-one".