640434600 has 240 divisors, whose sum is σ = 2396213820. Its totient is φ = 157593600.

The previous prime is 640434581. The next prime is 640434649. The reversal of 640434600 is 6434046.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 309267396 + 331167204 = 17586^2 + 18198^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 209080 + ... + 212120.

Almost surely, 2^640434600 is an apocalyptic number.

640434600 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 640434600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1198106910).

640434600 is an abundant number, since it is smaller than the sum of its proper divisors (1755779220).

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

640434600 is a wasteful number, since it uses less digits than its factorization.

640434600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3082 (or 3064 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 27.

The square root of 640434600 is about 25306.8093603283. The cubic root of 640434600 is about 861.9688979829.

Adding to 640434600 its reverse (6434046), we get a palindrome (646868646).

The spelling of 640434600 in words is "six hundred forty million, four hundred thirty-four thousand, six hundred".