12519966821 has 2 divisors, whose sum is σ = 12519966822. Its totient is φ = 12519966820.

The previous prime is 12519966769. The next prime is 12519966839. The reversal of 12519966821 is 12866991521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12368553796 + 151413025 = 111214^2 + 12305^2 .

It is an emirp because it is prime and its reverse (12866991521) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12519966821 - 2⁶ = 12519966757 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 12519966821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12519966841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6259983410 + 6259983411.

It is an arithmetic number, because the mean of its divisors is an integer number (6259983411).

Almost surely, 2^12519966821 is an apocalyptic number.

It is an amenable number.

12519966821 is a deficient number, since it is larger than the sum of its proper divisors (1).

12519966821 is an equidigital number, since it uses as much as digits as its factorization.

12519966821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 466560, while the sum is 50.

The spelling of 12519966821 in words is "twelve billion, five hundred nineteen million, nine hundred sixty-six thousand, eight hundred twenty-one".