21843841 has 4 divisors (see below), whose sum is σ = 21866500. Its totient is φ = 21821184.

The previous prime is 21843839. The next prime is 21843851. The reversal of 21843841 is 14834812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7403841 + 14440000 = 2721^2 + 3800^2 .

It is a cyclic number.

It is not a de Polignac number, because 21843841 - 2¹ = 21843839 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21843821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9816 + ... + 11833.

It is an arithmetic number, because the mean of its divisors is an integer number (5466625).

Almost surely, 2^21843841 is an apocalyptic number.

It is an amenable number.

21843841 is a deficient number, since it is larger than the sum of its proper divisors (22659).

21843841 is a wasteful number, since it uses less digits than its factorization.

21843841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22658.

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

The square root of 21843841 is about 4673.7395092153. The cubic root of 21843841 is about 279.5393829786.

The spelling of 21843841 in words is "twenty-one million, eight hundred forty-three thousand, eight hundred forty-one".