640321640352 has 144 divisors (see below), whose sum is σ = 1855851215400. Its totient is φ = 209347946496.

The previous prime is 640321640267. The next prime is 640321640353. The reversal of 640321640352 is 253046123046.

640321640352 is a `hidden beast` number, since 6 + 4 + 0 + 3 + 2 + 1 + 640 + 3 + 5 + 2 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 620383070736 + 19938569616 = 787644^2 + 141204^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (640321640353) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 84818274 + ... + 84825822.

Almost surely, 2^640321640352 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640321640352, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (927925607700).

640321640352 is an abundant number, since it is smaller than the sum of its proper divisors (1215529575048).

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

640321640352 is a wasteful number, since it uses less digits than its factorization.

640321640352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13175 (or 13164 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

Adding to 640321640352 its reverse (253046123046), we get a palindrome (893367763398).

The spelling of 640321640352 in words is "six hundred forty billion, three hundred twenty-one million, six hundred forty thousand, three hundred fifty-two".