21103843 has 2 divisors, whose sum is σ = 21103844. Its totient is φ = 21103842.

The previous prime is 21103759. The next prime is 21103847. The reversal of 21103843 is 34830112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21103843 is a prime.

It is not a weakly prime, because it can be changed into another prime (21103847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551921 + 10551922.

It is an arithmetic number, because the mean of its divisors is an integer number (10551922).

Almost surely, 2^21103843 is an apocalyptic number.

21103843 is a deficient number, since it is larger than the sum of its proper divisors (1).

21103843 is an equidigital number, since it uses as much as digits as its factorization.

21103843 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21103843 is about 4593.8919229777. The cubic root of 21103843 is about 276.3464240289.

Adding to 21103843 its reverse (34830112), we get a palindrome (55933955).

The spelling of 21103843 in words is "twenty-one million, one hundred three thousand, eight hundred forty-three".