1688881 has 4 divisors (see below), whose sum is σ = 1697652. Its totient is φ = 1680112.

The previous prime is 1688861. The next prime is 1688887. The reversal of 1688881 is 1888861.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1221025 + 467856 = 1105^2 + 684^2 .

It is a cyclic number.

It is not a de Polignac number, because 1688881 - 2⁹ = 1688369 is a prime.

It is a super-2 number, since 2×1688881² = 5704638064322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1688887) 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, 4090 + ... + 4483.

It is an arithmetic number, because the mean of its divisors is an integer number (424413).

2^1688881 is an apocalyptic number.

It is an amenable number.

1688881 is a deficient number, since it is larger than the sum of its proper divisors (8771).

1688881 is an equidigital number, since it uses as much as digits as its factorization.

1688881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8770.

The product of its digits is 24576, while the sum is 40.

The square root of 1688881 is about 1299.5695441184. The cubic root of 1688881 is about 119.0875470919.

The spelling of 1688881 in words is "one million, six hundred eighty-eight thousand, eight hundred eighty-one".