640352354521664 has 112 divisors (see below), whose sum is σ = 1317280391331840. Its totient is φ = 308652881349120.

The previous prime is 640352354521657. The next prime is 640352354521667. The reversal of 640352354521664 is 466125453253046.

It is a super-2 number, since 2×640352354521664² (a number of 30 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (640352354521667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 220454249 + ... + 223340055.

Almost surely, 2^{640352354521664} is an apocalyptic number.

640352354521664 is a gapful number since it is divisible by the number (64) 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 640352354521664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (658640195665920).

640352354521664 is an abundant number, since it is smaller than the sum of its proper divisors (676928036810176).

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

640352354521664 is a wasteful number, since it uses less digits than its factorization.

640352354521664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2886976 (or 2886966 counting only the distinct ones).

The product of its (nonzero) digits is 62208000, while the sum is 56.

The spelling of 640352354521664 in words is "six hundred forty trillion, three hundred fifty-two billion, three hundred fifty-four million, five hundred twenty-one thousand, six hundred sixty-four".