21043103 has 4 divisors (see below), whose sum is σ = 21053088. Its totient is φ = 21033120.

The previous prime is 21043097. The next prime is 21043111. The reversal of 21043103 is 30134012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21043103 - 2²⁴ = 4265887 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 (21043123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 458 + ... + 6503.

It is an arithmetic number, because the mean of its divisors is an integer number (5263272).

Almost surely, 2^21043103 is an apocalyptic number.

21043103 is a deficient number, since it is larger than the sum of its proper divisors (9985).

21043103 is an equidigital number, since it uses as much as digits as its factorization.

21043103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9984.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21043103 is about 4587.2762070754. The cubic root of 21043103 is about 276.0810472267.

Adding to 21043103 its reverse (30134012), we get a palindrome (51177115).

Subtracting 21043103 from its reverse (30134012), we obtain a palindrome (9090909).

The spelling of 21043103 in words is "twenty-one million, forty-three thousand, one hundred three".