21841943 has 4 divisors (see below), whose sum is σ = 22149648. Its totient is φ = 21534240.

The previous prime is 21841913. The next prime is 21842021. The reversal of 21841943 is 34914812.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21841943 - 2⁶ = 21841879 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21841913) 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 in 3 ways as a sum of consecutive naturals, for example, 153746 + ... + 153887.

It is an arithmetic number, because the mean of its divisors is an integer number (5537412).

Almost surely, 2^21841943 is an apocalyptic number.

21841943 is a deficient number, since it is larger than the sum of its proper divisors (307705).

21841943 is an equidigital number, since it uses as much as digits as its factorization.

21841943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307704.

The product of its digits is 6912, while the sum is 32.

The square root of 21841943 is about 4673.5364554051. The cubic root of 21841943 is about 279.5312864002.

The spelling of 21841943 in words is "twenty-one million, eight hundred forty-one thousand, nine hundred forty-three".