1666660193856 has 840 divisors, whose sum is σ = 5993808606720. Its totient is φ = 456180221952.

The previous prime is 1666660193837. The next prime is 1666660193867. The reversal of 1666660193856 is 6583910666661.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a junction number, because it is equal to n+sod(n) for n = 1666660193793 and 1666660193802.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 578901025 + ... + 578903903.

Almost surely, 2^{1666660193856} is an apocalyptic number.

1666660193856 is a gapful number since it is divisible by the number (16) 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 1666660193856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2996904303360).

1666660193856 is an abundant number, since it is smaller than the sum of its proper divisors (4327148412864).

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

1666660193856 is a wasteful number, since it uses less digits than its factorization.

1666660193856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3013 (or 2987 counting only the distinct ones).

The product of its (nonzero) digits is 50388480, while the sum is 63.

The spelling of 1666660193856 in words is "one trillion, six hundred sixty-six billion, six hundred sixty million, one hundred ninety-three thousand, eight hundred fifty-six".