1689840 has 60 divisors (see below), whose sum is σ = 5677464. Its totient is φ = 450432.

The previous prime is 1689829. The next prime is 1689847. The reversal of 1689840 is 489861.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (60).

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

It is a junction number, because it is equal to n+sod(n) for n = 1689795 and 1689804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1689847) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 454 + ... + 1893.

2^1689840 is an apocalyptic number.

1689840 is a gapful number since it is divisible by the number (10) 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 1689840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2838732).

1689840 is an abundant number, since it is smaller than the sum of its proper divisors (3987624).

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

1689840 is a wasteful number, since it uses less digits than its factorization.

1689840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2366 (or 2357 counting only the distinct ones).

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

The square root of 1689840 is about 1299.9384600819. The cubic root of 1689840 is about 119.1100833843.

The spelling of 1689840 in words is "one million, six hundred eighty-nine thousand, eight hundred forty".