1666816 has 36 divisors (see below), whose sum is σ = 3532032. Its totient is φ = 782336.

The previous prime is 1666811. The next prime is 1666823. The reversal of 1666816 is 6186661.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a zygodrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4161 + ... + 4543.

It is an arithmetic number, because the mean of its divisors is an integer number (98112).

2^1666816 is an apocalyptic number.

1666816 is a gapful number since it is divisible by the number (16) 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 1666816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1766016).

1666816 is an abundant number, since it is smaller than the sum of its proper divisors (1865216).

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

1666816 is an equidigital number, since it uses as much as digits as its factorization.

1666816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 416 (or 402 counting only the distinct ones).

The product of its digits is 10368, while the sum is 34.

The square root of 1666816 is about 1291.0522839916. The cubic root of 1666816 is about 118.5666511288.

The spelling of 1666816 in words is "one million, six hundred sixty-six thousand, eight hundred sixteen".