21012259 has 2 divisors, whose sum is σ = 21012260. Its totient is φ = 21012258.

The previous prime is 21012241. The next prime is 21012281. The reversal of 21012259 is 95221012.

It is an a-pointer prime, because the next prime (21012281) can be obtained adding 21012259 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21012259 - 2⁵ = 21012227 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21012239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506129 + 10506130.

It is an arithmetic number, because the mean of its divisors is an integer number (10506130).

Almost surely, 2^21012259 is an apocalyptic number.

21012259 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012259 is an equidigital number, since it uses as much as digits as its factorization.

21012259 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 21012259 is about 4583.9130663659. The cubic root of 21012259 is about 275.9460923561.

The spelling of 21012259 in words is "twenty-one million, twelve thousand, two hundred fifty-nine".