21238843 has 2 divisors, whose sum is σ = 21238844. Its totient is φ = 21238842.

The previous prime is 21238757. The next prime is 21238859. The reversal of 21238843 is 34883212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21238843 - 2¹⁷ = 21107771 is a prime.

It is not a weakly prime, because it can be changed into another prime (21238873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10619421 + 10619422.

It is an arithmetic number, because the mean of its divisors is an integer number (10619422).

Almost surely, 2^21238843 is an apocalyptic number.

21238843 is a deficient number, since it is larger than the sum of its proper divisors (1).

21238843 is an equidigital number, since it uses as much as digits as its factorization.

21238843 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9216, while the sum is 31.

The square root of 21238843 is about 4608.5619232034. The cubic root of 21238843 is about 276.9344290831.

The spelling of 21238843 in words is "twenty-one million, two hundred thirty-eight thousand, eight hundred forty-three".