1666320 has 80 divisors (see below), whose sum is σ = 5303232. Its totient is φ = 432640.

The previous prime is 1666309. The next prime is 1666321. The reversal of 1666320 is 236661.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (1666321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12655 + ... + 12785.

2^1666320 is an apocalyptic number.

1666320 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 1666320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2651616).

1666320 is an abundant number, since it is smaller than the sum of its proper divisors (3636912).

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

1666320 is a wasteful number, since it uses less digits than its factorization.

1666320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200 (or 194 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 24.

The square root of 1666320 is about 1290.8601783307. The cubic root of 1666320 is about 118.5548892040.

The spelling of 1666320 in words is "one million, six hundred sixty-six thousand, three hundred twenty".