12665719385449 has 27 divisors (see below), whose sum is σ = 14173244820567. Its totient is φ = 11313009068400.

The previous prime is 12665719385381. The next prime is 12665719385471. The reversal of 12665719385449 is 94458391756621.

The square root of 12665719385449 is 3558893.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1873627128025 + 10792092257424 = 1368805^2 + 3285132^2 .

It is not a de Polignac number, because 12665719385449 - 2⁷ = 12665719385321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12665719385849) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1434229464 + ... + 1434238294.

Almost surely, 2^{12665719385449} is an apocalyptic number.

12665719385449 is the 3558893-rd square number.

12665719385449 is the 1779447-th centered octagonal number.

It is an amenable number.

12665719385449 is a deficient number, since it is larger than the sum of its proper divisors (1507525435118).

12665719385449 is an frugal number, since it uses more digits than its factorization.

12665719385449 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17750 (or 8875 counting only the distinct ones).

The product of its digits is 391910400, while the sum is 70.

The spelling of 12665719385449 in words is "twelve trillion, six hundred sixty-five billion, seven hundred nineteen million, three hundred eighty-five thousand, four hundred forty-nine".