12538640 has 20 divisors (see below), whose sum is σ = 29152524. Its totient is φ = 5015424.

The previous prime is 12538633. The next prime is 12538649. The reversal of 12538640 is 4683521.

12538640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 5161984 + 7376656 = 2272^2 + 2716^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (12538649) 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, 78287 + ... + 78446.

Almost surely, 2^12538640 is an apocalyptic number.

12538640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12538640 is an abundant number, since it is smaller than the sum of its proper divisors (16613884).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12538640 is a wasteful number, since it uses less digits than its factorization.

12538640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156746 (or 156740 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 12538640 is about 3540.9942106702. The cubic root of 12538640 is about 232.3183303553.

The spelling of 12538640 in words is "twelve million, five hundred thirty-eight thousand, six hundred forty".