21202399 has 2 divisors, whose sum is σ = 21202400. Its totient is φ = 21202398.

The previous prime is 21202387. The next prime is 21202403. The reversal of 21202399 is 99320212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21202399 - 2⁵ = 21202367 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21202199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601199 + 10601200.

It is an arithmetic number, because the mean of its divisors is an integer number (10601200).

Almost surely, 2^21202399 is an apocalyptic number.

21202399 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202399 is an equidigital number, since it uses as much as digits as its factorization.

21202399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 21202399 is about 4604.6062806716. The cubic root of 21202399 is about 276.7759399646.

The spelling of 21202399 in words is "twenty-one million, two hundred two thousand, three hundred ninety-nine".