12505400321 has 4 divisors (see below), whose sum is σ = 12546134832. Its totient is φ = 12464665812.

The previous prime is 12505400293. The next prime is 12505400339. The reversal of 12505400321 is 12300450521.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12300450521 = 17 ⋅723555913.

It is a cyclic number.

It is not a de Polignac number, because 12505400321 - 2²⁶ = 12438291457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12505403321) 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, 20366795 + ... + 20367408.

It is an arithmetic number, because the mean of its divisors is an integer number (3136533708).

Almost surely, 2^12505400321 is an apocalyptic number.

It is an amenable number.

12505400321 is a deficient number, since it is larger than the sum of its proper divisors (40734511).

12505400321 is an equidigital number, since it uses as much as digits as its factorization.

12505400321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40734510.

The product of its (nonzero) digits is 1200, while the sum is 23.

Adding to 12505400321 its reverse (12300450521), we get a palindrome (24805850842).

The spelling of 12505400321 in words is "twelve billion, five hundred five million, four hundred thousand, three hundred twenty-one".