640322431620 has 96 divisors (see below), whose sum is σ = 1837826686080. Its totient is φ = 166488161280.

The previous prime is 640322431597. The next prime is 640322431627. The reversal of 640322431620 is 26134223046.

It is not an unprimeable number, because it can be changed into a prime (640322431627) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1249930 + ... + 1686110.

It is an arithmetic number, because the mean of its divisors is an integer number (19144027980).

Almost surely, 2^640322431620 is an apocalyptic number.

640322431620 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640322431620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (918913343040).

640322431620 is an abundant number, since it is smaller than the sum of its proper divisors (1197504254460).

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

640322431620 is a wasteful number, since it uses less digits than its factorization.

640322431620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 436805 (or 436803 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 33.

Adding to 640322431620 its reverse (26134223046), we get a palindrome (666456654666).

The spelling of 640322431620 in words is "six hundred forty billion, three hundred twenty-two million, four hundred thirty-one thousand, six hundred twenty".