21260663 has 2 divisors, whose sum is σ = 21260664. Its totient is φ = 21260662.

The previous prime is 21260651. The next prime is 21260669. The reversal of 21260663 is 36606212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21260663 - 2⁴ = 21260647 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21260669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10630331 + 10630332.

It is an arithmetic number, because the mean of its divisors is an integer number (10630332).

Almost surely, 2^21260663 is an apocalyptic number.

21260663 is a deficient number, since it is larger than the sum of its proper divisors (1).

21260663 is an equidigital number, since it uses as much as digits as its factorization.

21260663 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 21260663 is about 4610.9286483310. The cubic root of 21260663 is about 277.0292340131.

Adding to 21260663 its reverse (36606212), we get a palindrome (57866875).

The spelling of 21260663 in words is "twenty-one million, two hundred sixty thousand, six hundred sixty-three".