12912787609 has 4 divisors (see below), whose sum is σ = 12919191604. Its totient is φ = 12906383616.

The previous prime is 12912787607. The next prime is 12912787621. The reversal of 12912787609 is 90678721921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90678721921 = 23 ⋅3942553127.

It can be written as a sum of positive squares in 2 ways, for example, as 4239963225 + 8672824384 = 65115^2 + 93128^2 .

It is a cyclic number.

It is not a de Polignac number, because 12912787609 - 2¹ = 12912787607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12912787607) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3198972 + ... + 3203005.

It is an arithmetic number, because the mean of its divisors is an integer number (3229797901).

Almost surely, 2^12912787609 is an apocalyptic number.

It is an amenable number.

12912787609 is a deficient number, since it is larger than the sum of its proper divisors (6403995).

12912787609 is an equidigital number, since it uses as much as digits as its factorization.

12912787609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6403994.

The product of its (nonzero) digits is 762048, while the sum is 52.

It can be divided in two parts, 1291 and 2787609, that added together give a square (2788900 = 1670²).

The spelling of 12912787609 in words is "twelve billion, nine hundred twelve million, seven hundred eighty-seven thousand, six hundred nine".