1666720 has 48 divisors (see below), whose sum is σ = 4300128. Its totient is φ = 605440.

The previous prime is 1666711. The next prime is 1666727. The reversal of 1666720 is 276661.

It is not an unprimeable number, because it can be changed into a prime (1666727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1287 + ... + 2233.

It is an arithmetic number, because the mean of its divisors is an integer number (89586).

2^1666720 is an apocalyptic number.

1666720 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 1666720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2150064).

1666720 is an abundant number, since it is smaller than the sum of its proper divisors (2633408).

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

1666720 is a wasteful number, since it uses less digits than its factorization.

1666720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 973 (or 965 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 1666720 is about 1291.0151044817. The cubic root of 1666720 is about 118.5643748094.

It can be divided in two parts, 166 and 6720, that added together give a palindrome (6886).

The spelling of 1666720 in words is "one million, six hundred sixty-six thousand, seven hundred twenty".