21843791 has 4 divisors (see below), whose sum is σ = 22255992. Its totient is φ = 21431592.

The previous prime is 21843769. The next prime is 21843799. The reversal of 21843791 is 19734812.

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 21843791 - 2¹⁰ = 21842767 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 (21843799) 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, 206021 + ... + 206126.

It is an arithmetic number, because the mean of its divisors is an integer number (5563998).

Almost surely, 2^21843791 is an apocalyptic number.

21843791 is a deficient number, since it is larger than the sum of its proper divisors (412201).

21843791 is an equidigital number, since it uses as much as digits as its factorization.

21843791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412200.

The product of its digits is 12096, while the sum is 35.

The square root of 21843791 is about 4673.7341601764. The cubic root of 21843791 is about 279.5391696923.

The spelling of 21843791 in words is "twenty-one million, eight hundred forty-three thousand, seven hundred ninety-one".