1666147680 has 144 divisors (see below), whose sum is σ = 5696308800. Its totient is φ = 443480064.

The previous prime is 1666147661. The next prime is 1666147733. The reversal of 1666147680 is 867416661.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1510009 + ... + 1511111.

It is an arithmetic number, because the mean of its divisors is an integer number (39557700).

Almost surely, 2^1666147680 is an apocalyptic number.

1666147680 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 1666147680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2848154400).

1666147680 is an abundant number, since it is smaller than the sum of its proper divisors (4030161120).

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

1666147680 is a wasteful number, since it uses less digits than its factorization.

1666147680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2173 (or 2162 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 1666147680 is about 40818.4722889037. The cubic root of 1666147680 is about 1185.5080233740.

The spelling of 1666147680 in words is "one billion, six hundred sixty-six million, one hundred forty-seven thousand, six hundred eighty".