640235646 has 12 divisors (see below), whose sum is σ = 1387177272. Its totient is φ = 213411876.

The previous prime is 640235641. The next prime is 640235663. The reversal of 640235646 is 646532046.

640235646 is a `hidden beast` number, since 6 + 4 + 0 + 2 + 3 + 5 + 646 = 666.

640235646 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 640235646.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640235641) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 17784306 + ... + 17784341.

It is an arithmetic number, because the mean of its divisors is an integer number (115598106).

Almost surely, 2^640235646 is an apocalyptic number.

640235646 is an abundant number, since it is smaller than the sum of its proper divisors (746941626).

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

640235646 is a wasteful number, since it uses less digits than its factorization.

640235646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35568655 (or 35568652 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

The square root of 640235646 is about 25302.8782157287. The cubic root of 640235646 is about 861.8796305170.

The spelling of 640235646 in words is "six hundred forty million, two hundred thirty-five thousand, six hundred forty-six".