21393313 has 2 divisors, whose sum is σ = 21393314. Its totient is φ = 21393312.

The previous prime is 21393299. The next prime is 21393367. The reversal of 21393313 is 31339312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20857489 + 535824 = 4567^2 + 732^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21393313 is a prime.

It is a super-2 number, since 2×21393313² = 915347682231938, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21093313) 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, 10696656 + 10696657.

It is an arithmetic number, because the mean of its divisors is an integer number (10696657).

Almost surely, 2^21393313 is an apocalyptic number.

It is an amenable number.

21393313 is a deficient number, since it is larger than the sum of its proper divisors (1).

21393313 is an equidigital number, since it uses as much as digits as its factorization.

21393313 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1458, while the sum is 25.

The square root of 21393313 is about 4625.2905854660. The cubic root of 21393313 is about 277.6041888886.

The spelling of 21393313 in words is "twenty-one million, three hundred ninety-three thousand, three hundred thirteen".