640420000 has 240 divisors, whose sum is σ = 1785478464. Its totient is φ = 224000000.

The previous prime is 640419953. The next prime is 640420007. The reversal of 640420000 is 24046.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (640420007) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 9019965 + ... + 9020035.

Almost surely, 2^640420000 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 640420000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (892739232).

640420000 is an abundant number, since it is smaller than the sum of its proper divisors (1145058464).

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

640420000 is a wasteful number, since it uses less digits than its factorization.

640420000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 640420000 is about 25306.5208987723. The cubic root of 640420000 is about 861.9623478259.

Adding to 640420000 its reverse (24046), we get a palindrome (640444046).

The spelling of 640420000 in words is "six hundred forty million, four hundred twenty thousand".