12123012421 has 4 divisors (see below), whose sum is σ = 13055551852. Its totient is φ = 11190472992.

The previous prime is 12123012383. The next prime is 12123012467. The reversal of 12123012421 is 12421032121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12421032121 = 4177 ⋅2973673.

It can be written as a sum of positive squares in 2 ways, for example, as 2847396321 + 9275616100 = 53361^2 + 96310^2 .

It is a cyclic number.

It is not a de Polignac number, because 12123012421 - 2⁹ = 12123011909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12123012481) 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, 466269696 + ... + 466269721.

It is an arithmetic number, because the mean of its divisors is an integer number (3263887963).

Almost surely, 2^12123012421 is an apocalyptic number.

It is an amenable number.

12123012421 is a deficient number, since it is larger than the sum of its proper divisors (932539431).

12123012421 is an equidigital number, since it uses as much as digits as its factorization.

12123012421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 932539430.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 12123012421 its reverse (12421032121), we get a palindrome (24544044542).

The spelling of 12123012421 in words is "twelve billion, one hundred twenty-three million, twelve thousand, four hundred twenty-one".