21421126123 has 4 divisors (see below), whose sum is σ = 21825298368. Its totient is φ = 21016953880.

The previous prime is 21421126099. The next prime is 21421126147. The reversal of 21421126123 is 32162112412.

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

It is an interprime number because it is at equal distance from previous prime (21421126099) and next prime (21421126147).

It is a cyclic number.

It is not a de Polignac number, because 21421126123 - 2²⁹ = 20884255211 is a prime.

It is a super-2 number, since 2×21421126123² (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 (21421126423) 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, 202086043 + ... + 202086148.

It is an arithmetic number, because the mean of its divisors is an integer number (5456324592).

Almost surely, 2^21421126123 is an apocalyptic number.

21421126123 is a deficient number, since it is larger than the sum of its proper divisors (404172245).

21421126123 is an equidigital number, since it uses as much as digits as its factorization.

21421126123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 404172244.

The product of its digits is 1152, while the sum is 25.

Adding to 21421126123 its reverse (32162112412), we get a palindrome (53583238535).

The spelling of 21421126123 in words is "twenty-one billion, four hundred twenty-one million, one hundred twenty-six thousand, one hundred twenty-three".