640543453420 has 96 divisors (see below), whose sum is σ = 1477664697600. Its totient is φ = 231809071104.

The previous prime is 640543453409. The next prime is 640543453423. The reversal of 640543453420 is 24354345046.

640543453420 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (640543453423) 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, 2700166 + ... + 2927794.

It is an arithmetic number, because the mean of its divisors is an integer number (15392340600).

Almost surely, 2^640543453420 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 640543453420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (738832348800).

640543453420 is an abundant number, since it is smaller than the sum of its proper divisors (837121244180).

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

640543453420 is a wasteful number, since it uses less digits than its factorization.

640543453420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227867 (or 227865 counting only the distinct ones).

The product of its (nonzero) digits is 691200, while the sum is 40.

Adding to 640543453420 its reverse (24354345046), we get a palindrome (664897798466).

The spelling of 640543453420 in words is "six hundred forty billion, five hundred forty-three million, four hundred fifty-three thousand, four hundred twenty".