640337 has 4 divisors (see below), whose sum is σ = 643236. Its totient is φ = 637440.

The previous prime is 640333. The next prime is 640363. The reversal of 640337 is 733046.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 450241 + 190096 = 671^2 + 436^2 .

It is a cyclic number.

It is not a de Polignac number, because 640337 - 2² = 640333 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640337.

It is not an unprimeable number, because it can be changed into a prime (640333) 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, 1088 + ... + 1569.

It is an arithmetic number, because the mean of its divisors is an integer number (160809).

2⁶⁴⁰³³⁷ is an apocalyptic number.

It is an amenable number.

640337 is a deficient number, since it is larger than the sum of its proper divisors (2899).

640337 is a wasteful number, since it uses less digits than its factorization.

640337 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2898.

The product of its (nonzero) digits is 1512, while the sum is 23.

The square root of 640337 is about 800.2105972805. The cubic root of 640337 is about 86.1925108740.

The spelling of 640337 in words is "six hundred forty thousand, three hundred thirty-seven".