640395 has 48 divisors (see below), whose sum is σ = 1347840. Its totient is φ = 274752.

The previous prime is 640369. The next prime is 640411. The reversal of 640395 is 593046.

It is a happy number.

640395 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 640395 - 2⁵ = 640363 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5932 + ... + 6038.

It is an arithmetic number, because the mean of its divisors is an integer number (28080).

2⁶⁴⁰³⁹⁵ is an apocalyptic number.

640395 is an abundant number, since it is smaller than the sum of its proper divisors (707445).

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

640395 is a wasteful number, since it uses less digits than its factorization.

640395 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144 (or 141 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 640395 is about 800.2468369197. The cubic root of 640395 is about 86.1951131572.

It can be divided in two parts, 640 and 395, that added together give a triangular number (1035 = T₄₅).

The spelling of 640395 in words is "six hundred forty thousand, three hundred ninety-five".