21563219 has 2 divisors, whose sum is σ = 21563220. Its totient is φ = 21563218.

The previous prime is 21563189. The next prime is 21563237. The reversal of 21563219 is 91236512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21563219 - 2⁸ = 21562963 is a prime.

It is a super-2 number, since 2×21563219² = 929944827283922, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21563191 and 21563200.

It is not a weakly prime, because it can be changed into another prime (21563249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10781609 + 10781610.

It is an arithmetic number, because the mean of its divisors is an integer number (10781610).

Almost surely, 2^21563219 is an apocalyptic number.

21563219 is a deficient number, since it is larger than the sum of its proper divisors (1).

21563219 is an equidigital number, since it uses as much as digits as its factorization.

21563219 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 29.

The square root of 21563219 is about 4643.6213239238. The cubic root of 21563219 is about 278.3371640223.

The spelling of 21563219 in words is "twenty-one million, five hundred sixty-three thousand, two hundred nineteen".