1681866 has 24 divisors (see below), whose sum is σ = 3669120.
Its totient is φ = 556776.
The previous prime is 1681853. The next prime is 1681871. The reversal of 1681866 is 6681861.
It is a Curzon number.
It is a self number, because there is not a number n which added to its sum of digits gives 1681866.
It is an unprimeable number.
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, 3805 + ... + 4223.
It is an arithmetic number, because the mean of its divisors is an integer number (152880).
21681866 is an apocalyptic number.
1681866 is an abundant number, since it is smaller than the sum of its proper divisors (1987254).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
1681866 is a wasteful number, since it uses less digits than its factorization.
1681866 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 650 (or 647 counting only the distinct ones).
The product of its digits is 13824, while the sum is 36.
The square root of 1681866 is about 1296.8677650401.
The cubic root of 1681866 is about 118.9224360967.
The spelling of 1681866 in words is "one million, six hundred eighty-one thousand, eight hundred sixty-six".