21103543 has 4 divisors (see below), whose sum is σ = 21400848. Its totient is φ = 20806240.

The previous prime is 21103531. The next prime is 21103549. The reversal of 21103543 is 34530112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21103543 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21103543.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21103549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 148546 + ... + 148687.

It is an arithmetic number, because the mean of its divisors is an integer number (5350212).

Almost surely, 2^21103543 is an apocalyptic number.

21103543 is a deficient number, since it is larger than the sum of its proper divisors (297305).

21103543 is an equidigital number, since it uses as much as digits as its factorization.

21103543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 297304.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21103543 is about 4593.8592708092. The cubic root of 21103543 is about 276.3451145625.

Adding to 21103543 its reverse (34530112), we get a palindrome (55633655).

The spelling of 21103543 in words is "twenty-one million, one hundred three thousand, five hundred forty-three".