12649728785 has 4 divisors (see below), whose sum is σ = 15179674548. Its totient is φ = 10119783024.

The previous prime is 12649728779. The next prime is 12649728799. The reversal of 12649728785 is 58782794621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58782794621 = 45389 ⋅1295089.

It can be written as a sum of positive squares in 2 ways, for example, as 4304540881 + 8345187904 = 65609^2 + 91352^2 .

It is a cyclic number.

It is not a de Polignac number, because 12649728785 - 2⁴ = 12649728769 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1264972874 + ... + 1264972883.

It is an arithmetic number, because the mean of its divisors is an integer number (3794918637).

Almost surely, 2^12649728785 is an apocalyptic number.

It is an amenable number.

12649728785 is a deficient number, since it is larger than the sum of its proper divisors (2529945763).

12649728785 is an equidigital number, since it uses as much as digits as its factorization.

12649728785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2529945762.

The product of its digits is 13547520, while the sum is 59.

The spelling of 12649728785 in words is "twelve billion, six hundred forty-nine million, seven hundred twenty-eight thousand, seven hundred eighty-five".