640342 has 8 divisors (see below), whose sum is σ = 964296. Its totient is φ = 318912.

The previous prime is 640333. The next prime is 640363. The reversal of 640342 is 243046.

640342 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is an unprimeable number.

640342 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 253 + ... + 1159.

It is an arithmetic number, because the mean of its divisors is an integer number (120537).

2⁶⁴⁰³⁴² is an apocalyptic number.

640342 is a deficient number, since it is larger than the sum of its proper divisors (323954).

640342 is a wasteful number, since it uses less digits than its factorization.

640342 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1262.

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 640342 is about 800.2137214520. The cubic root of 640342 is about 86.1927352150.

Adding to 640342 its reverse (243046), we get a palindrome (883388).

The spelling of 640342 in words is "six hundred forty thousand, three hundred forty-two".