1665871200000 has 648 divisors, whose sum is σ = 6861364657056. Its totient is φ = 380759040000.

The previous prime is 1665871199999. The next prime is 1665871200041. The reversal of 1665871200000 is 21785661.

1665871200000 is a `hidden beast` number, since 1 + 66 + 587 + 12 + 0 + 0 + 0 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 50383474 + ... + 50416526.

Almost surely, 2^{1665871200000} is an apocalyptic number.

1665871200000 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 1665871200000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3430682328528).

1665871200000 is an abundant number, since it is smaller than the sum of its proper divisors (5195493457056).

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

1665871200000 is an frugal number, since it uses more digits than its factorization.

1665871200000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33107 (or 33070 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

Adding to 1665871200000 its reverse (21785661), we get a palindrome (1665892985661).

The spelling of 1665871200000 in words is "one trillion, six hundred sixty-five billion, eight hundred seventy-one million, two hundred thousand".