640002 has 16 divisors (see below), whose sum is σ = 1396512. Its totient is φ = 193920.

The previous prime is 639997. The next prime is 640007. The reversal of 640002 is 200046.

It is an interprime number because it is at equal distance from previous prime (639997) and next prime (640007).

It is a self number, because there is not a number n which added to its sum of digits gives 640002.

It is not an unprimeable number, because it can be changed into a prime (640007) by changing a digit.

640002 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4783 + ... + 4914.

It is an arithmetic number, because the mean of its divisors is an integer number (87282).

2⁶⁴⁰⁰⁰² is an apocalyptic number.

640002 is an abundant number, since it is smaller than the sum of its proper divisors (756510).

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

640002 is a wasteful number, since it uses less digits than its factorization.

640002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9713.

The product of its (nonzero) digits is 48, while the sum is 12.

The square root of 640002 is about 800.0012499990. The cubic root of 640002 is about 86.1774773693.

Adding to 640002 its reverse (200046), we get a palindrome (840048).

The spelling of 640002 in words is "six hundred forty thousand, two".