21311103123 has 24 divisors (see below), whose sum is σ = 32904537120. Its totient is φ = 13258227840.

The previous prime is 21311103113. The next prime is 21311103127. The reversal of 21311103123 is 32130111312.

It is not a de Polignac number, because 21311103123 - 2⁶ = 21311103059 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21311103096 and 21311103105.

It is not an unprimeable number, because it can be changed into a prime (21311103127) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1247028 + ... + 1264001.

It is an arithmetic number, because the mean of its divisors is an integer number (1371022380).

Almost surely, 2^21311103123 is an apocalyptic number.

21311103123 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21311103123 is a deficient number, since it is larger than the sum of its proper divisors (11593433997).

21311103123 is a wasteful number, since it uses less digits than its factorization.

21311103123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2511099 (or 2511096 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

Adding to 21311103123 its reverse (32130111312), we get a palindrome (53441214435).

The spelling of 21311103123 in words is "twenty-one billion, three hundred eleven million, one hundred three thousand, one hundred twenty-three".