640530000 has 300 divisors, whose sum is σ = 2447441568. Its totient is φ = 155040000.

The previous prime is 640529999. The next prime is 640530001. The reversal of 640530000 is 35046.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (640529999) and next prime (640530001).

It is a tau number, because it is divible by the number of its divisors (300).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640530001) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 989677 + ... + 990323.

Almost surely, 2^640530000 is an apocalyptic number.

640530000 is a gapful number since it is divisible by the number (60) 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 640530000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1223720784).

640530000 is an abundant number, since it is smaller than the sum of its proper divisors (1806911568).

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

640530000 is a wasteful number, since it uses less digits than its factorization.

640530000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 692 (or 668 counting only the distinct ones).

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

The square root of 640530000 is about 25308.6941583322. The cubic root of 640530000 is about 862.0116958737.

Adding to 640530000 its reverse (35046), we get a palindrome (640565046).

The spelling of 640530000 in words is "six hundred forty million, five hundred thirty thousand".