21061259 has 2 divisors, whose sum is σ = 21061260. Its totient is φ = 21061258.

The previous prime is 21061237. The next prime is 21061309. The reversal of 21061259 is 95216012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21061259 - 2²⁰ = 20012683 is a prime.

It is not a weakly prime, because it can be changed into another prime (21061459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10530629 + 10530630.

It is an arithmetic number, because the mean of its divisors is an integer number (10530630).

Almost surely, 2^21061259 is an apocalyptic number.

21061259 is a deficient number, since it is larger than the sum of its proper divisors (1).

21061259 is an equidigital number, since it uses as much as digits as its factorization.

21061259 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 21061259 is about 4589.2547325247. The cubic root of 21061259 is about 276.1604253580.

The spelling of 21061259 in words is "twenty-one million, sixty-one thousand, two hundred fifty-nine".