640435536 has 240 divisors, whose sum is σ = 2047368960. Its totient is φ = 185472000.

The previous prime is 640435493. The next prime is 640435559. The reversal of 640435536 is 635534046.

640435536 is a `hidden beast` number, since 64 + 0 + 43 + 553 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 640435536.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2551411 + ... + 2551661.

It is an arithmetic number, because the mean of its divisors is an integer number (8530704).

Almost surely, 2^640435536 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640435536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1023684480).

640435536 is an abundant number, since it is smaller than the sum of its proper divisors (1406933424).

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

640435536 is a wasteful number, since it uses less digits than its factorization.

640435536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 354 (or 345 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 36.

The square root of 640435536 is about 25306.8278533680. The cubic root of 640435536 is about 861.9693179074.

The spelling of 640435536 in words is "six hundred forty million, four hundred thirty-five thousand, five hundred thirty-six".