640343 has 8 divisors (see below), whose sum is σ = 729216. Its totient is φ = 556600.

The previous prime is 640333. The next prime is 640363. The reversal of 640343 is 343046.

It is a happy number.

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

It is not a de Polignac number, because 640343 - 2⁶ = 640279 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640343.

It is not an unprimeable number, because it can be changed into a prime (640303) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1013 + ... + 1518.

It is an arithmetic number, because the mean of its divisors is an integer number (91152).

2⁶⁴⁰³⁴³ is an apocalyptic number.

640343 is a deficient number, since it is larger than the sum of its proper divisors (88873).

640343 is a wasteful number, since it uses less digits than its factorization.

640343 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2565.

The product of its (nonzero) digits is 864, while the sum is 20.

The square root of 640343 is about 800.2143462848. The cubic root of 640343 is about 86.1927800830.

Adding to 640343 its reverse (343046), we get a palindrome (983389).

It can be divided in two parts, 6403 and 43, that added together give a palindrome (6446).

The spelling of 640343 in words is "six hundred forty thousand, three hundred forty-three".