640028210 has 8 divisors (see below), whose sum is σ = 1152050796. Its totient is φ = 256011280.

The previous prime is 640028209. The next prime is 640028219. The reversal of 640028210 is 12820046.

It can be written as a sum of positive squares in 2 ways, for example, as 613206169 + 26822041 = 24763^2 + 5179^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×640028210² = 819272219191608200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (640028219) 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, 32001401 + ... + 32001420.

Almost surely, 2^640028210 is an apocalyptic number.

640028210 is a deficient number, since it is larger than the sum of its proper divisors (512022586).

640028210 is a wasteful number, since it uses less digits than its factorization.

640028210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64002828.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 640028210 is about 25298.7788242832. The cubic root of 640028210 is about 861.7865376189.

Adding to 640028210 its reverse (12820046), we get a palindrome (652848256).

The spelling of 640028210 in words is "six hundred forty million, twenty-eight thousand, two hundred ten".