21384841 has 2 divisors, whose sum is σ = 21384842. Its totient is φ = 21384840.

The previous prime is 21384829. The next prime is 21384877. The reversal of 21384841 is 14848312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15523600 + 5861241 = 3940^2 + 2421^2 .

It is a cyclic number.

It is not a de Polignac number, because 21384841 - 2⁵ = 21384809 is a prime.

It is a super-2 number, since 2×21384841² = 914622849190562, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21384241) 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, 10692420 + 10692421.

It is an arithmetic number, because the mean of its divisors is an integer number (10692421).

Almost surely, 2^21384841 is an apocalyptic number.

It is an amenable number.

21384841 is a deficient number, since it is larger than the sum of its proper divisors (1).

21384841 is an equidigital number, since it uses as much as digits as its factorization.

21384841 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6144, while the sum is 31.

The square root of 21384841 is about 4624.3746604271. The cubic root of 21384841 is about 277.5675392244.

The spelling of 21384841 in words is "twenty-one million, three hundred eighty-four thousand, eight hundred forty-one".