21111103 has 4 divisors (see below), whose sum is σ = 22735048. Its totient is φ = 19487160.

The previous prime is 21111073. The next prime is 21111113. The reversal of 21111103 is 30111112.

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

It is a cyclic number.

It is not a de Polignac number, because 21111103 - 2⁹ = 21110591 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 21111103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111113) 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, 811953 + ... + 811978.

It is an arithmetic number, because the mean of its divisors is an integer number (5683762).

Almost surely, 2^21111103 is an apocalyptic number.

21111103 is a deficient number, since it is larger than the sum of its proper divisors (1623945).

21111103 is a wasteful number, since it uses less digits than its factorization.

21111103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1623944.

The product of its (nonzero) digits is 6, while the sum is 10.

The square root of 21111103 is about 4594.6820347006. The cubic root of 21111103 is about 276.3781093325.

Adding to 21111103 its reverse (30111112), we get a palindrome (51222215).

Subtracting 21111103 from its reverse (30111112), we obtain a palindrome (9000009).

The spelling of 21111103 in words is "twenty-one million, one hundred eleven thousand, one hundred three".