640206 has 24 divisors (see below), whose sum is σ = 1585584. Its totient is φ = 182880.

The previous prime is 640193. The next prime is 640219. The reversal of 640206 is 602046.

640206 is a `hidden beast` number, since 640 + 20 + 6 = 666.

640206 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (640193) and next prime (640219).

It is a Harshad number since it is a multiple of its sum of digits (18).

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 640206.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2415 + ... + 2666.

It is an arithmetic number, because the mean of its divisors is an integer number (66066).

2⁶⁴⁰²⁰⁶ is an apocalyptic number.

640206 is an abundant number, since it is smaller than the sum of its proper divisors (945378).

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

640206 is a wasteful number, since it uses less digits than its factorization.

640206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5096 (or 5093 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 640206 is about 800.1287396413. The cubic root of 640206 is about 86.1866327250.

The spelling of 640206 in words is "six hundred forty thousand, two hundred six".