12947778550666 has 4 divisors (see below), whose sum is σ = 19421667826002. Its totient is φ = 6473889275332.

The previous prime is 12947778550627. The next prime is 12947778550667. The reversal of 12947778550666 is 66605587774921.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 11507502537441 + 1440276013225 = 3392271^2 + 1200115^2 .

It is not an unprimeable number, because it can be changed into a prime (12947778550667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3236944637665 + ... + 3236944637668.

Almost surely, 2^{12947778550666} is an apocalyptic number.

12947778550666 is a deficient number, since it is larger than the sum of its proper divisors (6473889275336).

12947778550666 is an equidigital number, since it uses as much as digits as its factorization.

12947778550666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6473889275335.

The product of its (nonzero) digits is 1066867200, while the sum is 73.

The spelling of 12947778550666 in words is "twelve trillion, nine hundred forty-seven billion, seven hundred seventy-eight million, five hundred fifty thousand, six hundred sixty-six".