640288 has 48 divisors (see below), whose sum is σ = 1469664. Its totient is φ = 271360.

The previous prime is 640279. The next prime is 640303. The reversal of 640288 is 882046.

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

640288 is a modest number, since divided by 288 gives 64 as remainder.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5931 + ... + 6037.

It is an arithmetic number, because the mean of its divisors is an integer number (30618).

2⁶⁴⁰²⁸⁸ is an apocalyptic number.

640288 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (734832).

640288 is an abundant number, since it is smaller than the sum of its proper divisors (829376).

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

640288 is a wasteful number, since it uses less digits than its factorization.

640288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145 (or 137 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 28.

The square root of 640288 is about 800.1799797546. The cubic root of 640288 is about 86.1903122709.

The spelling of 640288 in words is "six hundred forty thousand, two hundred eighty-eight".