640963866 has 8 divisors (see below), whose sum is σ = 1281927744. Its totient is φ = 213654620.

The previous prime is 640963861. The next prime is 640963907. The reversal of 640963866 is 668369046.

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

640963866 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (640963861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53413650 + ... + 53413661.

It is an arithmetic number, because the mean of its divisors is an integer number (160240968).

Almost surely, 2^640963866 is an apocalyptic number.

640963866 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

640963866 is a wasteful number, since it uses less digits than its factorization.

640963866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106827316.

The product of its (nonzero) digits is 1119744, while the sum is 48.

The square root of 640963866 is about 25317.2641886915. The cubic root of 640963866 is about 862.2062811677.

The spelling of 640963866 in words is "six hundred forty million, nine hundred sixty-three thousand, eight hundred sixty-six".