640441206 has 24 divisors (see below), whose sum is σ = 1388106720. Its totient is φ = 213405936.

The previous prime is 640441201. The next prime is 640441231. The reversal of 640441206 is 602144046.

640441206 is a `hidden beast` number, since 640 + 4 + 4 + 12 + 0 + 6 = 666.

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 640441206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640441201) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 76915 + ... + 84833.

It is an arithmetic number, because the mean of its divisors is an integer number (57837780).

Almost surely, 2^640441206 is an apocalyptic number.

640441206 is an abundant number, since it is smaller than the sum of its proper divisors (747665514).

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

640441206 is a wasteful number, since it uses less digits than its factorization.

640441206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12420 (or 12417 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The square root of 640441206 is about 25306.9398782231. The cubic root of 640441206 is about 861.9718616719.

The spelling of 640441206 in words is "six hundred forty million, four hundred forty-one thousand, two hundred six".