1665172080000 has 1920 divisors, whose sum is σ = 7307235936000. Its totient is φ = 372003840000.

The previous prime is 1665172079993. The next prime is 1665172080031. The reversal of 1665172080000 is 802715661.

1665172080000 is a `hidden beast` number, since 1 + 66 + 517 + 2 + 0 + 80 + 0 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1920).

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 239 ways as a sum of consecutive naturals, for example, 2779919701 + ... + 2779920299.

It is an arithmetic number, because the mean of its divisors is an integer number (3805852050).

Almost surely, 2^{1665172080000} is an apocalyptic number.

1665172080000 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 1665172080000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3653617968000).

1665172080000 is an abundant number, since it is smaller than the sum of its proper divisors (5642063856000).

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

1665172080000 is an equidigital number, since it uses as much as digits as its factorization.

1665172080000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 672 (or 633 counting only the distinct ones).

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

Adding to 1665172080000 its reverse (802715661), we get a palindrome (1665974795661).

The spelling of 1665172080000 in words is "one trillion, six hundred sixty-five billion, one hundred seventy-two million, eighty thousand".