21207259 has 2 divisors, whose sum is σ = 21207260. Its totient is φ = 21207258.

The previous prime is 21207239. The next prime is 21207269. The reversal of 21207259 is 95270212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21207259 - 2⁹ = 21206747 is a prime.

It is not a weakly prime, because it can be changed into another prime (21207229) 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, 10603629 + 10603630.

It is an arithmetic number, because the mean of its divisors is an integer number (10603630).

Almost surely, 2^21207259 is an apocalyptic number.

21207259 is a deficient number, since it is larger than the sum of its proper divisors (1).

21207259 is an equidigital number, since it uses as much as digits as its factorization.

21207259 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 21207259 is about 4605.1339828500. The cubic root of 21207259 is about 276.7970858155.

The spelling of 21207259 in words is "twenty-one million, two hundred seven thousand, two hundred fifty-nine".