21211203123 has 12 divisors (see below), whose sum is σ = 33423714168. Its totient is φ = 12855274560.

The previous prime is 21211203121. The next prime is 21211203199. The reversal of 21211203123 is 32130211212.

It is not a de Polignac number, because 21211203123 - 2¹ = 21211203121 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21211203096 and 21211203105.

It is not an unprimeable number, because it can be changed into a prime (21211203121) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 107127190 + ... + 107127387.

It is an arithmetic number, because the mean of its divisors is an integer number (2785309514).

Almost surely, 2^21211203123 is an apocalyptic number.

21211203123 is a deficient number, since it is larger than the sum of its proper divisors (12212511045).

21211203123 is a wasteful number, since it uses less digits than its factorization.

21211203123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214254594 (or 214254591 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21211203123 its reverse (32130211212), we get a palindrome (53341414335).

The spelling of 21211203123 in words is "twenty-one billion, two hundred eleven million, two hundred three thousand, one hundred twenty-three".