1999866 has 32 divisors (see below), whose sum is σ = 4413888. Its totient is φ = 599040.

The previous prime is 1999859. The next prime is 1999867. The reversal of 1999866 is 6689991.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1999867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10266 + ... + 10458.

It is an arithmetic number, because the mean of its divisors is an integer number (137934).

2^1999866 is an apocalyptic number.

1999866 is an abundant number, since it is smaller than the sum of its proper divisors (2414022).

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

1999866 is a wasteful number, since it uses less digits than its factorization.

1999866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 366.

The product of its digits is 209952, while the sum is 48.

The square root of 1999866 is about 1414.1661854252. The cubic root of 1999866 is about 125.9892911030.

The spelling of 1999866 in words is "one million, nine hundred ninety-nine thousand, eight hundred sixty-six".