12865781 has 4 divisors (see below), whose sum is σ = 12896064. Its totient is φ = 12835500.

The previous prime is 12865771. The next prime is 12865813. The reversal of 12865781 is 18756821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 12865781 - 2¹⁰ = 12864757 is a prime.

It is a super-2 number, since 2×12865781² = 331056641479922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12865711) by changing a digit.

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

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14495 + ... + 15356.

It is an arithmetic number, because the mean of its divisors is an integer number (3224016).

Almost surely, 2^12865781 is an apocalyptic number.

It is an amenable number.

12865781 is a deficient number, since it is larger than the sum of its proper divisors (30283).

12865781 is an equidigital number, since it uses as much as digits as its factorization.

12865781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30282.

The product of its digits is 26880, while the sum is 38.

The square root of 12865781 is about 3586.8901572253. The cubic root of 12865781 is about 234.3214529168.

The spelling of 12865781 in words is "twelve million, eight hundred sixty-five thousand, seven hundred eighty-one".