21365219 has 2 divisors, whose sum is σ = 21365220. Its totient is φ = 21365218.

The previous prime is 21365203. The next prime is 21365221. The reversal of 21365219 is 91256312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21365219 - 2⁴ = 21365203 is a prime.

It is a super-2 number, since 2×21365219² = 912945165835922, which contains 22 as substring.

Together with 21365221, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_1351586 and since 21365219 and 1351586 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21365191 and 21365200.

It is not a weakly prime, because it can be changed into another prime (21365269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10682609 + 10682610.

It is an arithmetic number, because the mean of its divisors is an integer number (10682610).

Almost surely, 2^21365219 is an apocalyptic number.

21365219 is a deficient number, since it is larger than the sum of its proper divisors (1).

21365219 is an equidigital number, since it uses as much as digits as its factorization.

21365219 is an evil number, because the sum of its binary digits is even.

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

The square root of 21365219 is about 4622.2525893767. The cubic root of 21365219 is about 277.4826177463.

The spelling of 21365219 in words is "twenty-one million, three hundred sixty-five thousand, two hundred nineteen".