6538640 has 60 divisors (see below), whose sum is σ = 15952476. Its totient is φ = 2490624.

The previous prime is 6538621. The next prime is 6538669. The reversal of 6538640 is 468356.

6538640 = T₃₂₅ + T₃₂₆ + ... + T₄₁₈.

It can be written as a sum of positive squares in 2 ways, for example, as 4276624 + 2262016 = 2068^2 + 1504^2 .

It is a junction number, because it is equal to n+sod(n) for n = 6538597 and 6538606.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 139097 + ... + 139143.

Almost surely, 2^6538640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6538640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7976238).

6538640 is an abundant number, since it is smaller than the sum of its proper divisors (9413836).

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

6538640 is a wasteful number, since it uses less digits than its factorization.

6538640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144 (or 91 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 6538640 is about 2557.0764556423. The cubic root of 6538640 is about 186.9946331879.

The spelling of 6538640 in words is "six million, five hundred thirty-eight thousand, six hundred forty".