21123031023 has 12 divisors (see below), whose sum is σ = 30534842520. Its totient is φ = 14071037136.

The previous prime is 21123031001. The next prime is 21123031057. The reversal of 21123031023 is 32013032112.

It is not a de Polignac number, because 21123031023 - 2⁶ = 21123030959 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21123030987 and 21123031005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123031123) 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, 903108 + ... + 926201.

It is an arithmetic number, because the mean of its divisors is an integer number (2544570210).

Almost surely, 2^21123031023 is an apocalyptic number.

21123031023 is a deficient number, since it is larger than the sum of its proper divisors (9411811497).

21123031023 is a wasteful number, since it uses less digits than its factorization.

21123031023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1830598 (or 1830595 counting only the distinct ones).

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

Adding to 21123031023 its reverse (32013032112), we get a palindrome (53136063135).

The spelling of 21123031023 in words is "twenty-one billion, one hundred twenty-three million, thirty-one thousand, twenty-three".