640241 has 4 divisors (see below), whose sum is σ = 731712. Its totient is φ = 548772.

The previous prime is 640231. The next prime is 640247. The reversal of 640241 is 142046.

640241 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 142046 = 2 ⋅71023.

It is a de Polignac number, because none of the positive numbers 2^k-640241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640247) 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, 45725 + ... + 45738.

It is an arithmetic number, because the mean of its divisors is an integer number (182928).

2⁶⁴⁰²⁴¹ is an apocalyptic number.

It is an amenable number.

640241 is a deficient number, since it is larger than the sum of its proper divisors (91471).

640241 is an equidigital number, since it uses as much as digits as its factorization.

640241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91470.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 640241 is about 800.1506108227. The cubic root of 640241 is about 86.1882033013.

Adding to 640241 its reverse (142046), we get a palindrome (782287).

The spelling of 640241 in words is "six hundred forty thousand, two hundred forty-one".