640258 has 8 divisors (see below), whose sum is σ = 969228. Its totient is φ = 317184.

The previous prime is 640249. The next prime is 640259. The reversal of 640258 is 852046.

It can be written as a sum of positive squares in 2 ways, for example, as 552049 + 88209 = 743^2 + 297^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (640259) 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, 1191 + ... + 1642.

2⁶⁴⁰²⁵⁸ is an apocalyptic number.

640258 is a deficient number, since it is larger than the sum of its proper divisors (328970).

640258 is a wasteful number, since it uses less digits than its factorization.

640258 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2948.

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 640258 is about 800.1612337523. The cubic root of 640258 is about 86.1889661320.

It can be divided in two parts, 640 and 258, that added together give a palindrome (898).

The spelling of 640258 in words is "six hundred forty thousand, two hundred fifty-eight".