640434 has 8 divisors (see below), whose sum is σ = 1280880. Its totient is φ = 213476.

The previous prime is 640421. The next prime is 640457. The reversal of 640434 is 434046.

640434 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.

640434 is an admirable number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 640434.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640434.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53364 + ... + 53375.

It is an arithmetic number, because the mean of its divisors is an integer number (160110).

2⁶⁴⁰⁴³⁴ is an apocalyptic number.

640434 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640434 is a wasteful number, since it uses less digits than its factorization.

640434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106744.

The product of its (nonzero) digits is 1152, while the sum is 21.

The square root of 640434 is about 800.2712040302. The cubic root of 640434 is about 86.1968628800.

The spelling of 640434 in words is "six hundred forty thousand, four hundred thirty-four".