1666660665600 has 2160 divisors, whose sum is σ = 7743101076480. Its totient is φ = 344881152000.

The previous prime is 1666660665569. The next prime is 1666660665613. The reversal of 1666660665600 is 65660666661.

It is a tau number, because it is divible by the number of its divisors (2160).

It is a Harshad number since it is a multiple of its sum of digits (54).

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, 1585785075 + ... + 1585786125.

Almost surely, 2^{1666660665600} is an apocalyptic number.

1666660665600 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 1666660665600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3871550538240).

1666660665600 is an abundant number, since it is smaller than the sum of its proper divisors (6076440410880).

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

1666660665600 is a wasteful number, since it uses less digits than its factorization.

1666660665600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1138 (or 1110 counting only the distinct ones).

The product of its (nonzero) digits is 8398080, while the sum is 54.

The spelling of 1666660665600 in words is "one trillion, six hundred sixty-six billion, six hundred sixty million, six hundred sixty-five thousand, six hundred".