12986781 has 4 divisors (see below), whose sum is σ = 17315712. Its totient is φ = 8657852.

The previous prime is 12986723. The next prime is 12986783. The reversal of 12986781 is 18768921.

12986781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 12986781 - 2⁷ = 12986653 is a prime.

It is a super-2 number, since 2×12986781² = 337312961483922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12986783) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2164461 + ... + 2164466.

It is an arithmetic number, because the mean of its divisors is an integer number (4328928).

Almost surely, 2^12986781 is an apocalyptic number.

It is an amenable number.

12986781 is a deficient number, since it is larger than the sum of its proper divisors (4328931).

12986781 is an equidigital number, since it uses as much as digits as its factorization.

12986781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4328930.

The product of its digits is 48384, while the sum is 42.

The square root of 12986781 is about 3603.7176637467. The cubic root of 12986781 is about 235.0537435554.

The spelling of 12986781 in words is "twelve million, nine hundred eighty-six thousand, seven hundred eighty-one".