1666728 has 48 divisors (see below), whose sum is σ = 5160480. Its totient is φ = 476064.

The previous prime is 1666727. The next prime is 1666729. The reversal of 1666728 is 8276661.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1666727) and next prime (1666729).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 1666692 and 1666701.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1150 + ... + 2157.

It is an arithmetic number, because the mean of its divisors is an integer number (107510).

2^1666728 is an apocalyptic number.

1666728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1666728 is an abundant number, since it is smaller than the sum of its proper divisors (3493752).

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

1666728 is a wasteful number, since it uses less digits than its factorization.

1666728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3326 (or 3319 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 1666728 is about 1291.0182028151. The cubic root of 1666728 is about 118.5645645060.

The spelling of 1666728 in words is "one million, six hundred sixty-six thousand, seven hundred twenty-eight".