640004252 has 12 divisors (see below), whose sum is σ = 1121311296. Its totient is φ = 319629600.

The previous prime is 640004231. The next prime is 640004257. The reversal of 640004252 is 252400046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640004257) 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 3 ways as a sum of consecutive naturals, for example, 89249 + ... + 96152.

It is an arithmetic number, because the mean of its divisors is an integer number (93442608).

Almost surely, 2^640004252 is an apocalyptic number.

It is an amenable number.

640004252 is a deficient number, since it is larger than the sum of its proper divisors (481307044).

640004252 is a wasteful number, since it uses less digits than its factorization.

640004252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186268 (or 186266 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 640004252 is about 25298.3053187363. The cubic root of 640004252 is about 861.7757844786.

Adding to 640004252 its reverse (252400046), we get a palindrome (892404298).

The spelling of 640004252 in words is "six hundred forty million, four thousand, two hundred fifty-two".