640530 has 48 divisors (see below), whose sum is σ = 1819584. Its totient is φ = 155040.

The previous prime is 640529. The next prime is 640531. The reversal of 640530 is 35046.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (640529) and next prime (640531).

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

It is not an unprimeable number, because it can be changed into a prime (640531) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 667 + ... + 1313.

It is an arithmetic number, because the mean of its divisors is an integer number (37908).

2⁶⁴⁰⁵³⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (909792).

640530 is an abundant number, since it is smaller than the sum of its proper divisors (1179054).

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

640530 is a wasteful number, since it uses less digits than its factorization.

640530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 671 (or 668 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

The square root of 640530 is about 800.3311814493. The cubic root of 640530 is about 86.2011695874.

Adding to 640530 its reverse (35046), we get a palindrome (675576).

The spelling of 640530 in words is "six hundred forty thousand, five hundred thirty".