12655715778 has 32 divisors (see below), whose sum is σ = 28519931520. Its totient is φ = 4159154160.

The previous prime is 12655715777. The next prime is 12655715783. The reversal of 12655715778 is 87751755621.

12655715778 is a `hidden beast` number, since 1 + 2 + 6 + 557 + 15 + 7 + 78 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12655715771) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1646625 + ... + 1654292.

It is an arithmetic number, because the mean of its divisors is an integer number (891247860).

Almost surely, 2^12655715778 is an apocalyptic number.

12655715778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

12655715778 is an abundant number, since it is smaller than the sum of its proper divisors (15864215742).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12655715778 is a wasteful number, since it uses less digits than its factorization.

12655715778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3300999 (or 3300993 counting only the distinct ones).

The product of its digits is 4116000, while the sum is 54.

The spelling of 12655715778 in words is "twelve billion, six hundred fifty-five million, seven hundred fifteen thousand, seven hundred seventy-eight".