21012112103 has 4 divisors (see below), whose sum is σ = 22118012760. Its totient is φ = 19906211448.

The previous prime is 21012112021. The next prime is 21012112109. The reversal of 21012112103 is 30121121012.

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 21012112103 - 2¹⁰ = 21012111079 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 (21012112109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 552950300 + ... + 552950337.

It is an arithmetic number, because the mean of its divisors is an integer number (5529503190).

Almost surely, 2^21012112103 is an apocalyptic number.

21012112103 is a deficient number, since it is larger than the sum of its proper divisors (1105900657).

21012112103 is a wasteful number, since it uses less digits than its factorization.

21012112103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1105900656.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21012112103 its reverse (30121121012), we get a palindrome (51133233115).

The spelling of 21012112103 in words is "twenty-one billion, twelve million, one hundred twelve thousand, one hundred three".