21226321 has 2 divisors, whose sum is σ = 21226322. Its totient is φ = 21226320.

The previous prime is 21226291. The next prime is 21226327. The reversal of 21226321 is 12362212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13608721 + 7617600 = 3689^2 + 2760^2 .

It is a cyclic number.

It is not a de Polignac number, because 21226321 - 2⁷ = 21226193 is a prime.

It is not a weakly prime, because it can be changed into another prime (21226327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10613160 + 10613161.

It is an arithmetic number, because the mean of its divisors is an integer number (10613161).

Almost surely, 2^21226321 is an apocalyptic number.

It is an amenable number.

21226321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21226321 is an equidigital number, since it uses as much as digits as its factorization.

21226321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 288, while the sum is 19.

The square root of 21226321 is about 4607.2031646108. The cubic root of 21226321 is about 276.8799933706.

Adding to 21226321 its reverse (12362212), we get a palindrome (33588533).

The spelling of 21226321 in words is "twenty-one million, two hundred twenty-six thousand, three hundred twenty-one".