1640544542728 has 80 divisors (see below), whose sum is σ = 3864514995180. Its totient is φ = 649006533504.

The previous prime is 1640544542719. The next prime is 1640544542729. The reversal of 1640544542728 is 8272454450461.

It can be written as a sum of positive squares in 2 ways, for example, as 1600928417284 + 39616125444 = 1265278^2 + 199038^2 .

It is a Harshad number since it is a multiple of its sum of digits (52).

It is not an unprimeable number, because it can be changed into a prime (1640544542729) 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 19 ways as a sum of consecutive naturals, for example, 3035275 + ... + 3534682.

Almost surely, 2^{1640544542728} is an apocalyptic number.

It is an amenable number.

1640544542728 is an abundant number, since it is smaller than the sum of its proper divisors (2223970452452).

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

1640544542728 is an equidigital number, since it uses as much as digits as its factorization.

1640544542728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6570004 (or 6569979 counting only the distinct ones).

The product of its (nonzero) digits is 8601600, while the sum is 52.

The spelling of 1640544542728 in words is "one trillion, six hundred forty billion, five hundred forty-four million, five hundred forty-two thousand, seven hundred twenty-eight".