1666087781760 has 576 divisors, whose sum is σ = 6116319321840. Its totient is φ = 433385717760.

The previous prime is 1666087781747. The next prime is 1666087781773. The reversal of 1666087781760 is 671877806661.

It is an interprime number because it is at equal distance from previous prime (1666087781747) and next prime (1666087781773).

It is a tau number, because it is divible by the number of its divisors (576).

It is a Smith number, since the sum of its digits (63) coincides with the sum of the digits of its prime factors.

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, 261425934 + ... + 261432306.

Almost surely, 2^{1666087781760} is an apocalyptic number.

1666087781760 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 1666087781760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3058159660920).

1666087781760 is an abundant number, since it is smaller than the sum of its proper divisors (4450231540080).

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

1666087781760 is an frugal number, since it uses more digits than its factorization.

1666087781760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6489 (or 6424 counting only the distinct ones).

The product of its (nonzero) digits is 28449792, while the sum is 63.

The spelling of 1666087781760 in words is "one trillion, six hundred sixty-six billion, eighty-seven million, seven hundred eighty-one thousand, seven hundred sixty".