21126943 has 2 divisors, whose sum is σ = 21126944. Its totient is φ = 21126942.

The previous prime is 21126929. The next prime is 21126961. The reversal of 21126943 is 34962112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21126943 - 2⁹ = 21126431 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21126983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10563471 + 10563472.

It is an arithmetic number, because the mean of its divisors is an integer number (10563472).

Almost surely, 2^21126943 is an apocalyptic number.

21126943 is a deficient number, since it is larger than the sum of its proper divisors (1).

21126943 is an equidigital number, since it uses as much as digits as its factorization.

21126943 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 28.

The square root of 21126943 is about 4596.4054433873. The cubic root of 21126943 is about 276.4472156979.

The spelling of 21126943 in words is "twenty-one million, one hundred twenty-six thousand, nine hundred forty-three".