1666223680000 has 400 divisors, whose sum is σ = 4551788086560. Its totient is φ = 604108800000.

The previous prime is 1666223679961. The next prime is 1666223680003. The reversal of 1666223680000 is 863226661.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (400).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (1666223680003) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 2009919586 + ... + 2009920414.

Almost surely, 2^{1666223680000} is an apocalyptic number.

1666223680000 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 1666223680000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2275894043280).

1666223680000 is an abundant number, since it is smaller than the sum of its proper divisors (2885564406560).

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

1666223680000 is an frugal number, since it uses more digits than its factorization.

1666223680000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1449 (or 1418 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 40.

The spelling of 1666223680000 in words is "one trillion, six hundred sixty-six billion, two hundred twenty-three million, six hundred eighty thousand".