1688641 has 4 divisors (see below), whose sum is σ = 1746900. Its totient is φ = 1630384.

The previous prime is 1688629. The next prime is 1688651. The reversal of 1688641 is 1468861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1468861 = 593 ⋅2477.

It can be written as a sum of positive squares in 2 ways, for example, as 1008016 + 680625 = 1004^2 + 825^2 .

It is a cyclic number.

It is not a de Polignac number, because 1688641 - 2¹¹ = 1686593 is a prime.

It is a Duffinian number.

1688641 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1688597 and 1688606.

It is not an unprimeable number, because it can be changed into a prime (1688651) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29086 + ... + 29143.

It is an arithmetic number, because the mean of its divisors is an integer number (436725).

2^1688641 is an apocalyptic number.

It is an amenable number.

1688641 is a deficient number, since it is larger than the sum of its proper divisors (58259).

1688641 is an equidigital number, since it uses as much as digits as its factorization.

1688641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58258.

The product of its digits is 9216, while the sum is 34.

The square root of 1688641 is about 1299.4772025703. The cubic root of 1688641 is about 119.0819058092.

The spelling of 1688641 in words is "one million, six hundred eighty-eight thousand, six hundred forty-one".