12891871 has 2 divisors, whose sum is σ = 12891872. Its totient is φ = 12891870.

The previous prime is 12891869. The next prime is 12891881. The reversal of 12891871 is 17819821.

It is a weak prime.

It is an emirp because it is prime and its reverse (17819821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12891871 - 2¹ = 12891869 is a prime.

Together with 12891869, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 12891871.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12891811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6445935 + 6445936.

It is an arithmetic number, because the mean of its divisors is an integer number (6445936).

Almost surely, 2^12891871 is an apocalyptic number.

12891871 is a deficient number, since it is larger than the sum of its proper divisors (1).

12891871 is an equidigital number, since it uses as much as digits as its factorization.

12891871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 37.

The square root of 12891871 is about 3590.5251705008. The cubic root of 12891871 is about 234.4797363238.

It can be divided in two parts, 1289 and 1871, that added together give a triangular number (3160 = T₇₉).

The spelling of 12891871 in words is "twelve million, eight hundred ninety-one thousand, eight hundred seventy-one".