21023111123 has 8 divisors (see below), whose sum is σ = 24585166848. Its totient is φ = 17600743944.

The previous prime is 21023111117. The next prime is 21023111129. The reversal of 21023111123 is 32111132012.

It is an interprime number because it is at equal distance from previous prime (21023111117) and next prime (21023111129).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21023111123 - 2²⁰ = 21022062547 is a prime.

It is a super-2 number, since 2×21023111123² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21023111129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34921811 + ... + 34922412.

It is an arithmetic number, because the mean of its divisors is an integer number (3073145856).

Almost surely, 2^21023111123 is an apocalyptic number.

21023111123 is a deficient number, since it is larger than the sum of its proper divisors (3562055725).

21023111123 is an equidigital number, since it uses as much as digits as its factorization.

21023111123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69844273.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21023111123 its reverse (32111132012), we get a palindrome (53134243135).

The spelling of 21023111123 in words is "twenty-one billion, twenty-three million, one hundred eleven thousand, one hundred twenty-three".