21393299 has 2 divisors, whose sum is σ = 21393300. Its totient is φ = 21393298.

The previous prime is 21393287. The next prime is 21393313. The reversal of 21393299 is 99239312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21393299 - 2⁴ = 21393283 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21393269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10696649 + 10696650.

It is an arithmetic number, because the mean of its divisors is an integer number (10696650).

Almost surely, 2^21393299 is an apocalyptic number.

21393299 is a deficient number, since it is larger than the sum of its proper divisors (1).

21393299 is an equidigital number, since it uses as much as digits as its factorization.

21393299 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26244, while the sum is 38.

The square root of 21393299 is about 4625.2890720473. The cubic root of 21393299 is about 277.6041283329.

The spelling of 21393299 in words is "twenty-one million, three hundred ninety-three thousand, two hundred ninety-nine".