21243252118123 has 4 divisors (see below), whose sum is σ = 24278002420720. Its totient is φ = 18208501815528.

The previous prime is 21243252118037. The next prime is 21243252118139. The reversal of 21243252118123 is 32181125234212.

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

It is a cyclic number.

It is not a de Polignac number, because 21243252118123 - 2²⁹ = 21242715247211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21243252118723) 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, 1517375151288 + ... + 1517375151301.

It is an arithmetic number, because the mean of its divisors is an integer number (6069500605180).

Almost surely, 2^{21243252118123} is an apocalyptic number.

21243252118123 is a deficient number, since it is larger than the sum of its proper divisors (3034750302597).

21243252118123 is an equidigital number, since it uses as much as digits as its factorization.

21243252118123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3034750302596.

The product of its digits is 46080, while the sum is 37.

The spelling of 21243252118123 in words is "twenty-one trillion, two hundred forty-three billion, two hundred fifty-two million, one hundred eighteen thousand, one hundred twenty-three".