12543834521 has 4 divisors (see below), whose sum is σ = 12552305844. Its totient is φ = 12535363200.

The previous prime is 12543834509. The next prime is 12543834533.

12543834521 is nontrivially palindromic in base 10.

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 (12543834509) and next prime (12543834533).

It can be written as a sum of positive squares in 2 ways, for example, as 2536633225 + 10007201296 = 50365^2 + 100036^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12543834521 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12543834221) 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, 4233440 + ... + 4236401.

It is an arithmetic number, because the mean of its divisors is an integer number (3138076461).

Almost surely, 2^12543834521 is an apocalyptic number.

It is an amenable number.

12543834521 is a deficient number, since it is larger than the sum of its proper divisors (8471323).

12543834521 is an equidigital number, since it uses as much as digits as its factorization.

12543834521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8471322.

The product of its digits is 115200, while the sum is 38.

The spelling of 12543834521 in words is "twelve billion, five hundred forty-three million, eight hundred thirty-four thousand, five hundred twenty-one".