21032399 has 2 divisors, whose sum is σ = 21032400. Its totient is φ = 21032398.

The previous prime is 21032387. The next prime is 21032437. The reversal of 21032399 is 99323012.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21032399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21032309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10516199 + 10516200.

It is an arithmetic number, because the mean of its divisors is an integer number (10516200).

Almost surely, 2^21032399 is an apocalyptic number.

21032399 is a deficient number, since it is larger than the sum of its proper divisors (1).

21032399 is an equidigital number, since it uses as much as digits as its factorization.

21032399 is an evil number, because the sum of its binary digits is even.

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

The square root of 21032399 is about 4586.1093532536. The cubic root of 21032399 is about 276.0342278842.

The spelling of 21032399 in words is "twenty-one million, thirty-two thousand, three hundred ninety-nine".