12785778 has 12 divisors (see below), whose sum is σ = 27702558. Its totient is φ = 4261920.

The previous prime is 12785777. The next prime is 12785779. The reversal of 12785778 is 87758721.

12785778 is a `hidden beast` number, since 1 + 2 + 78 + 577 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (12785777) and next prime (12785779).

It can be written as a sum of positive squares in only one way, i.e., 7601049 + 5184729 = 2757^2 + 2277^2 .

It is a super-2 number, since 2×12785778² = 326952238130568, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (12785771) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 355143 + ... + 355178.

Almost surely, 2^12785778 is an apocalyptic number.

12785778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

12785778 is an abundant number, since it is smaller than the sum of its proper divisors (14916780).

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

12785778 is a wasteful number, since it uses less digits than its factorization.

12785778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 710329 (or 710326 counting only the distinct ones).

The product of its digits is 219520, while the sum is 45.

The square root of 12785778 is about 3575.7206266709. The cubic root of 12785778 is about 233.8347507413.

It can be divided in two parts, 1278 and 5778, that added together give a square (7056 = 84²).

The spelling of 12785778 in words is "twelve million, seven hundred eighty-five thousand, seven hundred seventy-eight".