12506781 has 32 divisors (see below), whose sum is σ = 20590848. Its totient is φ = 6589440.

The previous prime is 12506771. The next prime is 12506783. The reversal of 12506781 is 18760521.

12506781 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12506781 - 2⁶ = 12506717 is a prime.

It is a super-2 number, since 2×12506781² = 312839141963922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12506783) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18591 + ... + 19251.

It is an arithmetic number, because the mean of its divisors is an integer number (643464).

Almost surely, 2^12506781 is an apocalyptic number.

It is an amenable number.

12506781 is a deficient number, since it is larger than the sum of its proper divisors (8084067).

12506781 is a wasteful number, since it uses less digits than its factorization.

12506781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 741.

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 12506781 is about 3536.4927541280. The cubic root of 12506781 is about 232.1214002462.

The spelling of 12506781 in words is "twelve million, five hundred six thousand, seven hundred eighty-one".