12891289 has 8 divisors (see below), whose sum is σ = 13173480. Its totient is φ = 12612096.

The previous prime is 12891259. The next prime is 12891353. The reversal of 12891289 is 98219821.

It can be written as a sum of positive squares in 4 ways, for example, as 4579600 + 8311689 = 2140^2 + 2883^2 .

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 12891289 - 2²¹ = 10794137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12891209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is an upside-down number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9357 + ... + 10645.

It is an arithmetic number, because the mean of its divisors is an integer number (1646685).

Almost surely, 2^12891289 is an apocalyptic number.

It is an amenable number.

12891289 is a deficient number, since it is larger than the sum of its proper divisors (282191).

12891289 is a wasteful number, since it uses less digits than its factorization.

12891289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1499.

The product of its digits is 20736, while the sum is 40.

The square root of 12891289 is about 3590.4441229464. Note that the first 3 decimals coincide. The cubic root of 12891289 is about 234.4762077628.

The spelling of 12891289 in words is "twelve million, eight hundred ninety-one thousand, two hundred eighty-nine".