640202020 has 12 divisors (see below), whose sum is σ = 1344424284. Its totient is φ = 256080800.

The previous prime is 640202011. The next prime is 640202021. The reversal of 640202020 is 20202046.

It can be written as a sum of positive squares in 2 ways, for example, as 227949604 + 412252416 = 15098^2 + 20304^2 .

640202020 is a modest number, since divided by 202020 gives 640 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 640201985 and 640202003.

It is not an unprimeable number, because it can be changed into a prime (640202021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16005031 + ... + 16005070.

It is an arithmetic number, because the mean of its divisors is an integer number (112035357).

Almost surely, 2^640202020 is an apocalyptic number.

It is an amenable number.

640202020 is an abundant number, since it is smaller than the sum of its proper divisors (704222264).

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

640202020 is a wasteful number, since it uses less digits than its factorization.

640202020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32010110 (or 32010108 counting only the distinct ones).

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

The square root of 640202020 is about 25302.2137371417. The cubic root of 640202020 is about 861.8645412438.

Adding to 640202020 its reverse (20202046), we get a palindrome (660404066).

The spelling of 640202020 in words is "six hundred forty million, two hundred two thousand, twenty".