640442330 has 64 divisors (see below), whose sum is σ = 1304626176. Its totient is φ = 224256000.

The previous prime is 640442323. The next prime is 640442333. The reversal of 640442330 is 33244046.

It is a self number, because there is not a number n which added to its sum of digits gives 640442330.

It is not an unprimeable number, because it can be changed into a prime (640442333) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 998810 + ... + 999450.

It is an arithmetic number, because the mean of its divisors is an integer number (20384784).

Almost surely, 2^640442330 is an apocalyptic number.

640442330 is an abundant number, since it is smaller than the sum of its proper divisors (664183846).

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

640442330 is a wasteful number, since it uses less digits than its factorization.

640442330 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 983.

The product of its (nonzero) digits is 6912, while the sum is 26.

The square root of 640442330 is about 25306.9620855606. The cubic root of 640442330 is about 861.9723659367.

Adding to 640442330 its reverse (33244046), we get a palindrome (673686376).

The spelling of 640442330 in words is "six hundred forty million, four hundred forty-two thousand, three hundred thirty".