640685034 has 48 divisors (see below), whose sum is σ = 1522890720. Its totient is φ = 193051680.

The previous prime is 640684991. The next prime is 640685039. The reversal of 640685034 is 430586046.

640685034 is a `hidden beast` number, since 640 + 6 + 8 + 5 + 0 + 3 + 4 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 640685034.

It is not an unprimeable number, because it can be changed into a prime (640685039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26404 + ... + 44480.

It is an arithmetic number, because the mean of its divisors is an integer number (31726890).

Almost surely, 2^640685034 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640685034, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (761445360).

640685034 is an abundant number, since it is smaller than the sum of its proper divisors (882205686).

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

640685034 is a wasteful number, since it uses less digits than its factorization.

640685034 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18275 (or 18272 counting only the distinct ones).

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

The square root of 640685034 is about 25311.7568335349. The cubic root of 640685034 is about 862.0812374203.

The spelling of 640685034 in words is "six hundred forty million, six hundred eighty-five thousand, thirty-four".