12919987261 has 2 divisors, whose sum is σ = 12919987262. Its totient is φ = 12919987260.

The previous prime is 12919987259. The next prime is 12919987313. The reversal of 12919987261 is 16278991921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11839616100 + 1080371161 = 108810^2 + 32869^2 .

It is a cyclic number.

It is not a de Polignac number, because 12919987261 - 2¹ = 12919987259 is a prime.

Together with 12919987259, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12919987361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6459993630 + 6459993631.

It is an arithmetic number, because the mean of its divisors is an integer number (6459993631).

Almost surely, 2^12919987261 is an apocalyptic number.

It is an amenable number.

12919987261 is a deficient number, since it is larger than the sum of its proper divisors (1).

12919987261 is an equidigital number, since it uses as much as digits as its factorization.

12919987261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 55.

The spelling of 12919987261 in words is "twelve billion, nine hundred nineteen million, nine hundred eighty-seven thousand, two hundred sixty-one".