21068563 has 2 divisors, whose sum is σ = 21068564. Its totient is φ = 21068562.

The previous prime is 21068543. The next prime is 21068569. The reversal of 21068563 is 36586012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21068563 is a prime.

It is not a weakly prime, because it can be changed into another prime (21068569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10534281 + 10534282.

It is an arithmetic number, because the mean of its divisors is an integer number (10534282).

Almost surely, 2^21068563 is an apocalyptic number.

21068563 is a deficient number, since it is larger than the sum of its proper divisors (1).

21068563 is an equidigital number, since it uses as much as digits as its factorization.

21068563 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 21068563 is about 4590.0504354528. The cubic root of 21068563 is about 276.1923456185.

The spelling of 21068563 in words is "twenty-one million, sixty-eight thousand, five hundred sixty-three".