21299959 has 2 divisors, whose sum is σ = 21299960. Its totient is φ = 21299958.

The previous prime is 21299953. The next prime is 21299983. The reversal of 21299959 is 95999212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21299959 - 2¹⁷ = 21168887 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21299953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10649979 + 10649980.

It is an arithmetic number, because the mean of its divisors is an integer number (10649980).

Almost surely, 2^21299959 is an apocalyptic number.

21299959 is a deficient number, since it is larger than the sum of its proper divisors (1).

21299959 is an equidigital number, since it uses as much as digits as its factorization.

21299959 is an evil number, because the sum of its binary digits is even.

The product of its digits is 131220, while the sum is 46.

The square root of 21299959 is about 4615.1878618318. The cubic root of 21299959 is about 277.1998063156.

The spelling of 21299959 in words is "twenty-one million, two hundred ninety-nine thousand, nine hundred fifty-nine".