1689666 has 16 divisors (see below), whose sum is σ = 3686688. Its totient is φ = 512000.

The previous prime is 1689661. The next prime is 1689703. The reversal of 1689666 is 6669861.

It is not an unprimeable number, because it can be changed into a prime (1689661) 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, 12735 + ... + 12866.

It is an arithmetic number, because the mean of its divisors is an integer number (230418).

2^1689666 is an apocalyptic number.

1689666 is an abundant number, since it is smaller than the sum of its proper divisors (1997022).

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

1689666 is a wasteful number, since it uses less digits than its factorization.

1689666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25617.

The product of its digits is 93312, while the sum is 42.

The square root of 1689666 is about 1299.8715321138. The cubic root of 1689666 is about 119.1059950552.

It can be divided in two parts, 16896 and 66, that multiplied together give a square (1115136 = 1056²).

The spelling of 1689666 in words is "one million, six hundred eighty-nine thousand, six hundred sixty-six".