640312 has 8 divisors (see below), whose sum is σ = 1200600. Its totient is φ = 320152.

The previous prime is 640307. The next prime is 640333. The reversal of 640312 is 213046.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40012 + ... + 40027.

It is an arithmetic number, because the mean of its divisors is an integer number (150075).

2⁶⁴⁰³¹² is an apocalyptic number.

It is an amenable number.

640312 is a deficient number, since it is larger than the sum of its proper divisors (560288).

640312 is a wasteful number, since it uses less digits than its factorization.

640312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80045 (or 80041 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 640312 is about 800.1949762402. The cubic root of 640312 is about 86.1913891518.

Adding to 640312 its reverse (213046), we get a palindrome (853358).

The spelling of 640312 in words is "six hundred forty thousand, three hundred twelve".