640552 has 32 divisors (see below), whose sum is σ = 1360800. Its totient is φ = 280000.

The previous prime is 640531. The next prime is 640579. The reversal of 640552 is 255046.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is an unprimeable number.

640552 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, 2427 + ... + 2677.

It is an arithmetic number, because the mean of its divisors is an integer number (42525).

2⁶⁴⁰⁵⁵² is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (680400).

640552 is an abundant number, since it is smaller than the sum of its proper divisors (720248).

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

640552 is a wasteful number, since it uses less digits than its factorization.

640552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297 (or 293 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 640552 is about 800.3449256414. The cubic root of 640552 is about 86.2021564805.

Adding to 640552 its reverse (255046), we get a palindrome (895598).

The spelling of 640552 in words is "six hundred forty thousand, five hundred fifty-two".