12756321 has 6 divisors (see below), whose sum is σ = 18425810. Its totient is φ = 8504208.

The previous prime is 12756319. The next prime is 12756343. The reversal of 12756321 is 12365721.

It is a happy number.

12756321 is a `hidden beast` number, since 1 + 27 + 5 + 632 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 8346321 + 4410000 = 2889^2 + 2100^2 .

It is not a de Polignac number, because 12756321 - 2¹ = 12756319 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12756311) 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, 708676 + ... + 708693.

Almost surely, 2^12756321 is an apocalyptic number.

It is an amenable number.

12756321 is a deficient number, since it is larger than the sum of its proper divisors (5669489).

12756321 is a wasteful number, since it uses less digits than its factorization.

12756321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1417375 (or 1417372 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 12756321 is about 3571.5992216373. The cubic root of 12756321 is about 233.6550363009.

The spelling of 12756321 in words is "twelve million, seven hundred fifty-six thousand, three hundred twenty-one".