12991687 has 8 divisors (see below), whose sum is σ = 13722800. Its totient is φ = 12265344.

The previous prime is 12991679. The next prime is 12991703. The reversal of 12991687 is 78619921.

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

It is a cyclic number.

It is not a de Polignac number, because 12991687 - 2³ = 12991679 is a prime.

It is a super-2 number, since 2×12991687² = 337567862211938, which contains 22 as substring.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12991087) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 5389 + ... + 7417.

It is an arithmetic number, because the mean of its divisors is an integer number (1715350).

Almost surely, 2^12991687 is an apocalyptic number.

12991687 is a deficient number, since it is larger than the sum of its proper divisors (731113).

12991687 is a wasteful number, since it uses less digits than its factorization.

12991687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2385.

The product of its digits is 54432, while the sum is 43.

The square root of 12991687 is about 3604.3982854285. The cubic root of 12991687 is about 235.0833384819.

The spelling of 12991687 in words is "twelve million, nine hundred ninety-one thousand, six hundred eighty-seven".