641540 has 12 divisors (see below), whose sum is σ = 1347276. Its totient is φ = 256608.

The previous prime is 641521. The next prime is 641549. The reversal of 641540 is 45146.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 495616 + 145924 = 704^2 + 382^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 32077 = 641540 / (6 + 4 + 1 + 5 + 4 + 0).

It is not an unprimeable number, because it can be changed into a prime (641549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16019 + ... + 16058.

It is an arithmetic number, because the mean of its divisors is an integer number (112273).

2⁶⁴¹⁵⁴⁰ is an apocalyptic number.

It is an amenable number.

641540 is an abundant number, since it is smaller than the sum of its proper divisors (705736).

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

641540 is a wasteful number, since it uses less digits than its factorization.

641540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32086 (or 32084 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 641540 is about 800.9619216917. The cubic root of 641540 is about 86.2464536804.

Adding to 641540 its reverse (45146), we get a palindrome (686686).

The spelling of 641540 in words is "six hundred forty-one thousand, five hundred forty".