640285 has 8 divisors (see below), whose sum is σ = 789336. Its totient is φ = 498240.

The previous prime is 640279. The next prime is 640303. The reversal of 640285 is 582046.

640285 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 91204 + 549081 = 302^2 + 741^2 .

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

It is not a de Polignac number, because 640285 - 2¹⁵ = 607517 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 1546 + ... + 1915.

It is an arithmetic number, because the mean of its divisors is an integer number (98667).

2⁶⁴⁰²⁸⁵ is an apocalyptic number.

It is an amenable number.

640285 is a deficient number, since it is larger than the sum of its proper divisors (149051).

640285 is a wasteful number, since it uses less digits than its factorization.

640285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3503.

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

The square root of 640285 is about 800.1781051741. The cubic root of 640285 is about 86.1901776589.

The spelling of 640285 in words is "six hundred forty thousand, two hundred eighty-five".