12891645 has 24 divisors (see below), whose sum is σ = 24065496. Its totient is φ = 6346368.

The previous prime is 12891623. The next prime is 12891647. The reversal of 12891645 is 54619821.

12891645 is a `hidden beast` number, since 1 + 2 + 8 + 9 + 1 + 645 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 125316 + 12766329 = 354^2 + 3573^2 .

It is not a de Polignac number, because 12891645 - 2⁷ = 12891517 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12891647) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10434 + ... + 11603.

It is an arithmetic number, because the mean of its divisors is an integer number (1002729).

Almost surely, 2^12891645 is an apocalyptic number.

12891645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

12891645 is a deficient number, since it is larger than the sum of its proper divisors (11173851).

12891645 is a wasteful number, since it uses less digits than its factorization.

12891645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22061 (or 22058 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 12891645 is about 3590.4936986437. The cubic root of 12891645 is about 234.4783661392.

The spelling of 12891645 in words is "twelve million, eight hundred ninety-one thousand, six hundred forty-five".