640995020 has 48 divisors (see below), whose sum is σ = 1426572000. Its totient is φ = 241251840.

The previous prime is 640995011. The next prime is 640995083. The reversal of 640995020 is 20599046.

640995020 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50960 + ... + 62280.

It is an arithmetic number, because the mean of its divisors is an integer number (29720250).

Almost surely, 2^640995020 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 640995020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (713286000).

640995020 is an abundant number, since it is smaller than the sum of its proper divisors (785576980).

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

640995020 is a wasteful number, since it uses less digits than its factorization.

640995020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11498 (or 11496 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 640995020 is about 25317.8794530664. The cubic root of 640995020 is about 862.2202500983.

The spelling of 640995020 in words is "six hundred forty million, nine hundred ninety-five thousand, twenty".