640008 has 32 divisors (see below), whose sum is σ = 1778400. Its totient is φ = 213264.

The previous prime is 640007. The next prime is 640009. The reversal of 640008 is 800046.

It is an interprime number because it is at equal distance from previous prime (640007) and next prime (640009).

It is a super-2 number, since 2×640008² = 819220480128, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 15.

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1266 + ... + 1697.

It is an arithmetic number, because the mean of its divisors is an integer number (55575).

2⁶⁴⁰⁰⁰⁸ is an apocalyptic number.

It is an amenable number.

640008 is an abundant number, since it is smaller than the sum of its proper divisors (1138392).

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

640008 is a wasteful number, since it uses less digits than its factorization.

640008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2978 (or 2968 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 640008 is about 800.0049999844. The cubic root of 640008 is about 86.1777466722.

It can be divided in two parts, 64000 and 8, that multiplied together give a cube (512000 = 80³).

The spelling of 640008 in words is "six hundred forty thousand, eight".