21103003123 has 4 divisors (see below), whose sum is σ = 21197635648. Its totient is φ = 21008370600.

The previous prime is 21103003109. The next prime is 21103003139. The reversal of 21103003123 is 32130030112.

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 21103003123 - 2⁹ = 21103002611 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21103003097 and 21103003106.

It is not an unprimeable number, because it can be changed into a prime (21103003423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47315928 + ... + 47316373.

It is an arithmetic number, because the mean of its divisors is an integer number (5299408912).

Almost surely, 2^21103003123 is an apocalyptic number.

21103003123 is a deficient number, since it is larger than the sum of its proper divisors (94632525).

21103003123 is an equidigital number, since it uses as much as digits as its factorization.

21103003123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94632524.

The product of its (nonzero) digits is 108, while the sum is 16.

Adding to 21103003123 its reverse (32130030112), we get a palindrome (53233033235).

The spelling of 21103003123 in words is "twenty-one billion, one hundred three million, three thousand, one hundred twenty-three".