640235286 has 64 divisors (see below), whose sum is σ = 1506700800. Its totient is φ = 200955168.

The previous prime is 640235243. The next prime is 640235293. The reversal of 640235286 is 682532046.

640235286 is a `hidden beast` number, since 640 + 2 + 3 + 5 + 2 + 8 + 6 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 640235286.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 175695 + ... + 179301.

It is an arithmetic number, because the mean of its divisors is an integer number (23542200).

Almost surely, 2^640235286 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640235286, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (753350400).

640235286 is an abundant number, since it is smaller than the sum of its proper divisors (866465514).

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

640235286 is a wasteful number, since it uses less digits than its factorization.

640235286 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3810 (or 3804 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The square root of 640235286 is about 25302.8711019125. The cubic root of 640235286 is about 861.8794689740.

The spelling of 640235286 in words is "six hundred forty million, two hundred thirty-five thousand, two hundred eighty-six".