12991647 has 8 divisors (see below), whose sum is σ = 17339056. Its totient is φ = 8652672.

The previous prime is 12991613. The next prime is 12991661. The reversal of 12991647 is 74619921.

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

It is not a de Polignac number, because 12991647 - 2¹² = 12987551 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12991747) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4113 + ... + 6549.

It is an arithmetic number, because the mean of its divisors is an integer number (2167382).

Almost surely, 2^12991647 is an apocalyptic number.

12991647 is a deficient number, since it is larger than the sum of its proper divisors (4347409).

12991647 is a wasteful number, since it uses less digits than its factorization.

12991647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4217.

The product of its digits is 27216, while the sum is 39.

The square root of 12991647 is about 3604.3927366479. The cubic root of 12991647 is about 235.0830972162.

The spelling of 12991647 in words is "twelve million, nine hundred ninety-one thousand, six hundred forty-seven".