21284519 has 2 divisors, whose sum is σ = 21284520. Its totient is φ = 21284518.

The previous prime is 21284491. The next prime is 21284533. The reversal of 21284519 is 91548212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21284519 - 2¹² = 21280423 is a prime.

It is a super-2 number, since 2×21284519² = 906061498122722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21283519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10642259 + 10642260.

It is an arithmetic number, because the mean of its divisors is an integer number (10642260).

Almost surely, 2^21284519 is an apocalyptic number.

21284519 is a deficient number, since it is larger than the sum of its proper divisors (1).

21284519 is an equidigital number, since it uses as much as digits as its factorization.

21284519 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 32.

The square root of 21284519 is about 4613.5148206113. The cubic root of 21284519 is about 277.1328108880.

The spelling of 21284519 in words is "twenty-one million, two hundred eighty-four thousand, five hundred nineteen".