21363259 has 4 divisors (see below), whose sum is σ = 21633760. Its totient is φ = 21092760.

The previous prime is 21363257. The next prime is 21363289. The reversal of 21363259 is 95236312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21363259 - 2¹ = 21363257 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21363259.

It is not an unprimeable number, because it can be changed into a prime (21363253) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 135132 + ... + 135289.

It is an arithmetic number, because the mean of its divisors is an integer number (5408440).

Almost surely, 2^21363259 is an apocalyptic number.

21363259 is a deficient number, since it is larger than the sum of its proper divisors (270501).

21363259 is an equidigital number, since it uses as much as digits as its factorization.

21363259 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 270500.

The product of its digits is 9720, while the sum is 31.

The square root of 21363259 is about 4622.0405666762. The cubic root of 21363259 is about 277.4741322640.

The spelling of 21363259 in words is "twenty-one million, three hundred sixty-three thousand, two hundred fifty-nine".