21021123103 has 4 divisors (see below), whose sum is σ = 21021416728. Its totient is φ = 21020829480.

The previous prime is 21021123041. The next prime is 21021123113. The reversal of 21021123103 is 30132112012.

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 a de Polignac number, because none of the positive numbers 2^k-21021123103 is a prime.

It is a super-2 number, since 2×21021123103² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021123113) 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, 38788 + ... + 208678.

It is an arithmetic number, because the mean of its divisors is an integer number (5255354182).

Almost surely, 2^21021123103 is an apocalyptic number.

21021123103 is a deficient number, since it is larger than the sum of its proper divisors (293625).

21021123103 is a wasteful number, since it uses less digits than its factorization.

21021123103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 293624.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21021123103 its reverse (30132112012), we get a palindrome (51153235115).

The spelling of 21021123103 in words is "twenty-one billion, twenty-one million, one hundred twenty-three thousand, one hundred three".