640322431566 has 8 divisors (see below), whose sum is σ = 1280644863144. Its totient is φ = 213440810520.

The previous prime is 640322431561. The next prime is 640322431597. The reversal of 640322431566 is 665134223046.

It is a happy number.

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

640322431566 is an admirable number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640322431561) 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, 53360202625 + ... + 53360202636.

It is an arithmetic number, because the mean of its divisors is an integer number (160080607893).

Almost surely, 2^640322431566 is an apocalyptic number.

640322431566 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.

640322431566 is a wasteful number, since it uses less digits than its factorization.

640322431566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106720405266.

The product of its (nonzero) digits is 622080, while the sum is 42.

The spelling of 640322431566 in words is "six hundred forty billion, three hundred twenty-two million, four hundred thirty-one thousand, five hundred sixty-six".