21867943 has 4 divisors (see below), whose sum is σ = 22622040. Its totient is φ = 21113848.

The previous prime is 21867941. The next prime is 21867949. The reversal of 21867943 is 34976812.

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 21867943 - 2¹ = 21867941 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21867896 and 21867905.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21867941) 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, 377005 + ... + 377062.

It is an arithmetic number, because the mean of its divisors is an integer number (5655510).

Almost surely, 2^21867943 is an apocalyptic number.

21867943 is a deficient number, since it is larger than the sum of its proper divisors (754097).

21867943 is an equidigital number, since it uses as much as digits as its factorization.

21867943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 754096.

The product of its digits is 72576, while the sum is 40.

The square root of 21867943 is about 4676.3172475785. The cubic root of 21867943 is about 279.6421576653.

The spelling of 21867943 in words is "twenty-one million, eight hundred sixty-seven thousand, nine hundred forty-three".