21023031123 has 12 divisors (see below), whose sum is σ = 30667261248. Its totient is φ = 13876587600.

The previous prime is 21023031119. The next prime is 21023031131. The reversal of 21023031123 is 32113032012.

It is not a de Polignac number, because 21023031123 - 2² = 21023031119 is a prime.

It is a super-2 number, since 2×21023031123² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21023031096 and 21023031105.

It is not an unprimeable number, because it can be changed into a prime (21023031163) 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, 11562915 + ... + 11564732.

It is an arithmetic number, because the mean of its divisors is an integer number (2555605104).

Almost surely, 2^21023031123 is an apocalyptic number.

21023031123 is a deficient number, since it is larger than the sum of its proper divisors (9644230125).

21023031123 is a wasteful number, since it uses less digits than its factorization.

21023031123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23127754 (or 23127751 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

Adding to 21023031123 its reverse (32113032012), we get a palindrome (53136063135).

The spelling of 21023031123 in words is "twenty-one billion, twenty-three million, thirty-one thousand, one hundred twenty-three".