12278781 has 6 divisors (see below), whose sum is σ = 17736030. Its totient is φ = 8185848.

The previous prime is 12278767. The next prime is 12278789. The reversal of 12278781 is 18787221.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 9272025 + 3006756 = 3045^2 + 1734^2 .

It is not a de Polignac number, because 12278781 - 2⁹ = 12278269 is a prime.

It is a super-2 number, since 2×12278781² = 301536925691922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12278789) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 682146 + ... + 682163.

It is an arithmetic number, because the mean of its divisors is an integer number (2956005).

Almost surely, 2^12278781 is an apocalyptic number.

It is an amenable number.

12278781 is a deficient number, since it is larger than the sum of its proper divisors (5457249).

12278781 is a wasteful number, since it uses less digits than its factorization.

12278781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1364315 (or 1364312 counting only the distinct ones).

The product of its digits is 12544, while the sum is 36.

The square root of 12278781 is about 3504.1091592586. The cubic root of 12278781 is about 230.7022080492.

The spelling of 12278781 in words is "twelve million, two hundred seventy-eight thousand, seven hundred eighty-one".