640544889600 has 1512 divisors, whose sum is σ = 2965301375232. Its totient is φ = 133025587200.

The previous prime is 640544889557. The next prime is 640544889623. The reversal of 640544889600 is 6988445046.

640544889600 is a `hidden beast` number, since 6 + 4 + 0 + 544 + 8 + 8 + 96 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1512).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

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 167 ways as a sum of consecutive naturals, for example, 359250309 + ... + 359252091.

Almost surely, 2^640544889600 is an apocalyptic number.

640544889600 is a gapful number since it is divisible by the number (60) 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 640544889600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1482650687616).

640544889600 is an abundant number, since it is smaller than the sum of its proper divisors (2324756485632).

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

640544889600 is a wasteful number, since it uses less digits than its factorization.

640544889600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1845 (or 1811 counting only the distinct ones).

The product of its (nonzero) digits is 6635520, while the sum is 54.

The spelling of 640544889600 in words is "six hundred forty billion, five hundred forty-four million, eight hundred eighty-nine thousand, six hundred".