1689408 has 84 divisors (see below), whose sum is σ = 5547360. Its totient is φ = 481536.

The previous prime is 1689397. The next prime is 1689431. The reversal of 1689408 is 8049861.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (84).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3823 + ... + 4241.

It is an arithmetic number, because the mean of its divisors is an integer number (66040).

2^1689408 is an apocalyptic number.

1689408 is a gapful number since it is divisible by the number (18) 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 1689408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2773680).

1689408 is an abundant number, since it is smaller than the sum of its proper divisors (3857952).

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

1689408 is a wasteful number, since it uses less digits than its factorization.

1689408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 444 (or 431 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 1689408 is about 1299.7722877489. The cubic root of 1689408 is about 119.0999325334.

The spelling of 1689408 in words is "one million, six hundred eighty-nine thousand, four hundred eight".