72538640 has 40 divisors (see below), whose sum is σ = 170976408. Its totient is φ = 28615680.

The previous prime is 72538639. The next prime is 72538663. The reversal of 72538640 is 4683527.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 27164944 + 45373696 = 5212^2 + 6736^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 72538640.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 371 + ... + 12050.

Almost surely, 2^72538640 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 72538640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85488204).

72538640 is an abundant number, since it is smaller than the sum of its proper divisors (98437768).

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

72538640 is a wasteful number, since it uses less digits than its factorization.

72538640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12507 (or 12501 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 35.

The square root of 72538640 is about 8516.9618996447. The cubic root of 72538640 is about 417.0516108314.

The spelling of 72538640 in words is "seventy-two million, five hundred thirty-eight thousand, six hundred forty".