12543249239921 has 2 divisors, whose sum is σ = 12543249239922. Its totient is φ = 12543249239920.

The previous prime is 12543249239903. The next prime is 12543249240077. The reversal of 12543249239921 is 12993294234521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12418301129521 + 124948110400 = 3523961^2 + 353480^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12543249239921 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (12543249239321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6271624619960 + 6271624619961.

It is an arithmetic number, because the mean of its divisors is an integer number (6271624619961).

Almost surely, 2^{12543249239921} is an apocalyptic number.

It is an amenable number.

12543249239921 is a deficient number, since it is larger than the sum of its proper divisors (1).

12543249239921 is an equidigital number, since it uses as much as digits as its factorization.

12543249239921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8398080, while the sum is 56.

The spelling of 12543249239921 in words is "twelve trillion, five hundred forty-three billion, two hundred forty-nine million, two hundred thirty-nine thousand, nine hundred twenty-one".