21293563 has 2 divisors, whose sum is σ = 21293564. Its totient is φ = 21293562.

The previous prime is 21293521. The next prime is 21293579. The reversal of 21293563 is 36539212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21293563 is a prime.

It is not a weakly prime, because it can be changed into another prime (21293263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10646781 + 10646782.

It is an arithmetic number, because the mean of its divisors is an integer number (10646782).

Almost surely, 2^21293563 is an apocalyptic number.

21293563 is a deficient number, since it is larger than the sum of its proper divisors (1).

21293563 is an equidigital number, since it uses as much as digits as its factorization.

21293563 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9720, while the sum is 31.

The square root of 21293563 is about 4614.4948802659. The cubic root of 21293563 is about 277.1720574757.

The spelling of 21293563 in words is "twenty-one million, two hundred ninety-three thousand, five hundred sixty-three".