640154173128 has 128 divisors (see below), whose sum is σ = 1728122342400. Its totient is φ = 197003955456.

The previous prime is 640154173121. The next prime is 640154173159. The reversal of 640154173128 is 821371451046.

It is a self number, because there is not a number n which added to its sum of digits gives 640154173128.

It is not an unprimeable number, because it can be changed into a prime (640154173121) 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, 75601551 + ... + 75610017.

It is an arithmetic number, because the mean of its divisors is an integer number (13500955800).

Almost surely, 2^640154173128 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 640154173128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (864061171200).

640154173128 is an abundant number, since it is smaller than the sum of its proper divisors (1087968169272).

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

640154173128 is a wasteful number, since it uses less digits than its factorization.

640154173128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13251 (or 13247 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 42.

The spelling of 640154173128 in words is "six hundred forty billion, one hundred fifty-four million, one hundred seventy-three thousand, one hundred twenty-eight".