21302399 has 2 divisors, whose sum is σ = 21302400. Its totient is φ = 21302398.

The previous prime is 21302389. The next prime is 21302419. The reversal of 21302399 is 99320312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21302399 - 2⁸ = 21302143 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21302389) 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, 10651199 + 10651200.

It is an arithmetic number, because the mean of its divisors is an integer number (10651200).

Almost surely, 2^21302399 is an apocalyptic number.

21302399 is a deficient number, since it is larger than the sum of its proper divisors (1).

21302399 is an equidigital number, since it uses as much as digits as its factorization.

21302399 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916, while the sum is 29.

The square root of 21302399 is about 4615.4521988642. The cubic root of 21302399 is about 277.2103907132.

The spelling of 21302399 in words is "twenty-one million, three hundred two thousand, three hundred ninety-nine".