1688040 has 80 divisors (see below), whose sum is σ = 5684580. Its totient is φ = 449280.

The previous prime is 1687999. The next prime is 1688041. The reversal of 1688040 is 408861.

It can be written as a sum of positive squares in 2 ways, for example, as 1633284 + 54756 = 1278^2 + 234^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 1687995 and 1688013.

It is not an unprimeable number, because it can be changed into a prime (1688041) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 2980 + ... + 3500.

2^1688040 is an apocalyptic number.

1688040 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 1688040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2842290).

1688040 is an abundant number, since it is smaller than the sum of its proper divisors (3996540).

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

1688040 is a wasteful number, since it uses less digits than its factorization.

1688040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 544 (or 531 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 1688040 is about 1299.2459351485. The cubic root of 1688040 is about 119.0677767517.

The spelling of 1688040 in words is "one million, six hundred eighty-eight thousand, forty".