21130223123 has 4 divisors (see below), whose sum is σ = 21131104680. Its totient is φ = 21129341568.

The previous prime is 21130223111. The next prime is 21130223129. The reversal of 21130223123 is 32132203112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21130223123 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21130223095 and 21130223104.

It is not an unprimeable number, because it can be changed into a prime (21130223129) 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, 403790 + ... + 453107.

It is an arithmetic number, because the mean of its divisors is an integer number (5282776170).

Almost surely, 2^21130223123 is an apocalyptic number.

21130223123 is a deficient number, since it is larger than the sum of its proper divisors (881557).

21130223123 is an equidigital number, since it uses as much as digits as its factorization.

21130223123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 881556.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21130223123 its reverse (32132203112), we get a palindrome (53262426235).

The spelling of 21130223123 in words is "twenty-one billion, one hundred thirty million, two hundred twenty-three thousand, one hundred twenty-three".