21226393 has 2 divisors, whose sum is σ = 21226394. Its totient is φ = 21226392.

The previous prime is 21226379. The next prime is 21226409. The reversal of 21226393 is 39362212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15904144 + 5322249 = 3988^2 + 2307^2 .

It is a cyclic number.

It is not a de Polignac number, because 21226393 - 2⁹ = 21225881 is a prime.

It is not a weakly prime, because it can be changed into another prime (21226193) 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, 10613196 + 10613197.

It is an arithmetic number, because the mean of its divisors is an integer number (10613197).

Almost surely, 2^21226393 is an apocalyptic number.

It is an amenable number.

21226393 is a deficient number, since it is larger than the sum of its proper divisors (1).

21226393 is an equidigital number, since it uses as much as digits as its factorization.

21226393 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 28.

The square root of 21226393 is about 4607.2109784554. The cubic root of 21226393 is about 276.8803064306.

It can be divided in two parts, 2122 and 6393, that added together give a triangular number (8515 = T₁₃₀).

The spelling of 21226393 in words is "twenty-one million, two hundred twenty-six thousand, three hundred ninety-three".