12991278 has 8 divisors (see below), whose sum is σ = 25982568. Its totient is φ = 4330424.

The previous prime is 12991267. The next prime is 12991291. The reversal of 12991278 is 87219921.

It is a sphenic number, since it is the product of 3 distinct primes.

12991278 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1082601 + ... + 1082612.

It is an arithmetic number, because the mean of its divisors is an integer number (3247821).

Almost surely, 2^12991278 is an apocalyptic number.

12991278 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

12991278 is a wasteful number, since it uses less digits than its factorization.

12991278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2165218.

The product of its digits is 18144, while the sum is 39.

The square root of 12991278 is about 3604.3415487437. The cubic root of 12991278 is about 235.0808715173.

The spelling of 12991278 in words is "twelve million, nine hundred ninety-one thousand, two hundred seventy-eight".