21821419 has 2 divisors, whose sum is σ = 21821420. Its totient is φ = 21821418.

The previous prime is 21821413. The next prime is 21821441. The reversal of 21821419 is 91412812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21821419 - 2¹⁹ = 21297131 is a prime.

It is a super-2 number, since 2×21821419² = 952348654347122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21821413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10910709 + 10910710.

It is an arithmetic number, because the mean of its divisors is an integer number (10910710).

Almost surely, 2^21821419 is an apocalyptic number.

21821419 is a deficient number, since it is larger than the sum of its proper divisors (1).

21821419 is an equidigital number, since it uses as much as digits as its factorization.

21821419 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1152, while the sum is 28.

The square root of 21821419 is about 4671.3401717280. The cubic root of 21821419 is about 279.4437041731.

The spelling of 21821419 in words is "twenty-one million, eight hundred twenty-one thousand, four hundred nineteen".