21136393 has 2 divisors, whose sum is σ = 21136394. Its totient is φ = 21136392.

The previous prime is 21136369. The next prime is 21136403. The reversal of 21136393 is 39363112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17867529 + 3268864 = 4227^2 + 1808^2 .

It is a cyclic number.

It is not a de Polignac number, because 21136393 - 2¹³ = 21128201 is a prime.

It is not a weakly prime, because it can be changed into another prime (21137393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10568196 + 10568197.

It is an arithmetic number, because the mean of its divisors is an integer number (10568197).

Almost surely, 2^21136393 is an apocalyptic number.

It is an amenable number.

21136393 is a deficient number, since it is larger than the sum of its proper divisors (1).

21136393 is an equidigital number, since it uses as much as digits as its factorization.

21136393 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2916, while the sum is 28.

The square root of 21136393 is about 4597.4333056609. The cubic root of 21136393 is about 276.4884274778.

The spelling of 21136393 in words is "twenty-one million, one hundred thirty-six thousand, three hundred ninety-three".