21384619 has 2 divisors, whose sum is σ = 21384620. Its totient is φ = 21384618.

The previous prime is 21384613. The next prime is 21384647. The reversal of 21384619 is 91648312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21384619 - 2¹⁹ = 20860331 is a prime.

It is a super-2 number, since 2×21384619² = 914603859550322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21384613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10692309 + 10692310.

It is an arithmetic number, because the mean of its divisors is an integer number (10692310).

Almost surely, 2^21384619 is an apocalyptic number.

21384619 is a deficient number, since it is larger than the sum of its proper divisors (1).

21384619 is an equidigital number, since it uses as much as digits as its factorization.

21384619 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 34.

The square root of 21384619 is about 4624.3506571193. The cubic root of 21384619 is about 277.5665787277.

The spelling of 21384619 in words is "twenty-one million, three hundred eighty-four thousand, six hundred nineteen".