1665522118800 has 720 divisors, whose sum is σ = 6173672806080. Its totient is φ = 426441093120.

The previous prime is 1665522118723. The next prime is 1665522118811. The reversal of 1665522118800 is 88112255661.

1665522118800 is a `hidden beast` number, since 1 + 6 + 6 + 5 + 522 + 118 + 8 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (45).

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 143 ways as a sum of consecutive naturals, for example, 2116292007 + ... + 2116292793.

It is an arithmetic number, because the mean of its divisors is an integer number (8574545564).

Almost surely, 2^{1665522118800} is an apocalyptic number.

1665522118800 is a gapful number since it is divisible by the number (10) 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 1665522118800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3086836403040).

1665522118800 is an abundant number, since it is smaller than the sum of its proper divisors (4508150687280).

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

1665522118800 is a wasteful number, since it uses less digits than its factorization.

1665522118800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1105 (or 1059 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 45.

The spelling of 1665522118800 in words is "one trillion, six hundred sixty-five billion, five hundred twenty-two million, one hundred eighteen thousand, eight hundred".