21411563 has 2 divisors, whose sum is σ = 21411564. Its totient is φ = 21411562.

The previous prime is 21411547. The next prime is 21411581. The reversal of 21411563 is 36511412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21411563 - 2⁴ = 21411547 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21411263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10705781 + 10705782.

It is an arithmetic number, because the mean of its divisors is an integer number (10705782).

Almost surely, 2^21411563 is an apocalyptic number.

21411563 is a deficient number, since it is larger than the sum of its proper divisors (1).

21411563 is an equidigital number, since it uses as much as digits as its factorization.

21411563 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 720, while the sum is 23.

The square root of 21411563 is about 4627.2630139209. The cubic root of 21411563 is about 277.6831050823.

Adding to 21411563 its reverse (36511412), we get a palindrome (57922975).

The spelling of 21411563 in words is "twenty-one million, four hundred eleven thousand, five hundred sixty-three".