21132123123 has 4 divisors (see below), whose sum is σ = 28176164168. Its totient is φ = 14088082080.

The previous prime is 21132123109. The next prime is 21132123163. The reversal of 21132123123 is 32132123112.

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

It is not a de Polignac number, because 21132123123 - 2¹² = 21132119027 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21132123123.

It is not an unprimeable number, because it can be changed into a prime (21132123163) 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, 3522020518 + ... + 3522020523.

It is an arithmetic number, because the mean of its divisors is an integer number (7044041042).

Almost surely, 2^21132123123 is an apocalyptic number.

21132123123 is a deficient number, since it is larger than the sum of its proper divisors (7044041045).

21132123123 is an equidigital number, since it uses as much as digits as its factorization.

21132123123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7044041044.

The product of its digits is 432, while the sum is 21.

Adding to 21132123123 its reverse (32132123112), we get a palindrome (53264246235).

The spelling of 21132123123 in words is "twenty-one billion, one hundred thirty-two million, one hundred twenty-three thousand, one hundred twenty-three".