640008811 has 12 divisors (see below), whose sum is σ = 706485136. Its totient is φ = 576348480.

The previous prime is 640008793. The next prime is 640008871. The reversal of 640008811 is 118800046.

It is a de Polignac number, because none of the positive numbers 2^k-640008811 is a prime.

It is a super-2 number, since 2×640008811² = 819222556315267442, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 640008811.

It is not an unprimeable number, because it can be changed into a prime (640008871) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7210 + ... + 36496.

Almost surely, 2^640008811 is an apocalyptic number.

640008811 is a deficient number, since it is larger than the sum of its proper divisors (66476325).

640008811 is a wasteful number, since it uses less digits than its factorization.

640008811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29382 (or 29341 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 640008811 is about 25298.3954234256. The cubic root of 640008811 is about 861.7778307288. Note that the first 3 decimals are identical.

Adding to 640008811 its reverse (118800046), we get a palindrome (758808857).

The spelling of 640008811 in words is "six hundred forty million, eight thousand, eight hundred eleven".