640435236 has 24 divisors (see below), whose sum is σ = 1707827520. Its totient is φ = 182981472.

The previous prime is 640435171. The next prime is 640435241. The reversal of 640435236 is 632534046.

It is a junction number, because it is equal to n+sod(n) for n = 640435197 and 640435206.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3812031 + ... + 3812198.

It is an arithmetic number, because the mean of its divisors is an integer number (71159480).

Almost surely, 2^640435236 is an apocalyptic number.

It is an amenable number.

640435236 is an abundant number, since it is smaller than the sum of its proper divisors (1067392284).

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

640435236 is a wasteful number, since it uses less digits than its factorization.

640435236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7624243 (or 7624241 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 33.

The square root of 640435236 is about 25306.8219261131. The cubic root of 640435236 is about 861.9691833163.

The spelling of 640435236 in words is "six hundred forty million, four hundred thirty-five thousand, two hundred thirty-six".