12991745 has 8 divisors (see below), whose sum is σ = 16789416. Its totient is φ = 9593856.

The previous prime is 12991733. The next prime is 12991747. The reversal of 12991745 is 54719921.

It can be written as a sum of positive squares in 4 ways, for example, as 2999824 + 9991921 = 1732^2 + 3161^2 .

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 12991745 - 2⁴ = 12991729 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12991699 and 12991708.

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, 99872 + ... + 100001.

It is an arithmetic number, because the mean of its divisors is an integer number (2098677).

Almost surely, 2^12991745 is an apocalyptic number.

It is an amenable number.

12991745 is a deficient number, since it is larger than the sum of its proper divisors (3797671).

12991745 is a wasteful number, since it uses less digits than its factorization.

12991745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199891.

The product of its digits is 22680, while the sum is 38.

The square root of 12991745 is about 3604.4063311453. The cubic root of 12991745 is about 235.0836883162.

The spelling of 12991745 in words is "twelve million, nine hundred ninety-one thousand, seven hundred forty-five".