12891861 has 12 divisors (see below), whose sum is σ = 19601920. Its totient is φ = 8142120.

The previous prime is 12891839. The next prime is 12891869. The reversal of 12891861 is 16819821.

It is not a de Polignac number, because 12891861 - 2⁵ = 12891829 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12891869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37525 + ... + 37866.

Almost surely, 2^12891861 is an apocalyptic number.

It is an amenable number.

12891861 is a deficient number, since it is larger than the sum of its proper divisors (6710059).

12891861 is a wasteful number, since it uses less digits than its factorization.

12891861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75416 (or 75413 counting only the distinct ones).

The product of its digits is 6912, while the sum is 36.

The square root of 12891861 is about 3590.5237779466. The cubic root of 12891861 is about 234.4796756965.

The spelling of 12891861 in words is "twelve million, eight hundred ninety-one thousand, eight hundred sixty-one".