1688431 has 4 divisors (see below), whose sum is σ = 1693864. Its totient is φ = 1683000.

The previous prime is 1688413. The next prime is 1688443. The reversal of 1688431 is 1348861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1348861 = 379 ⋅3559.

It is a cyclic number.

It is not a de Polignac number, because 1688431 - 2¹⁵ = 1655663 is a prime.

It is a super-2 number, since 2×1688431² = 5701598483522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1688393 and 1688402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1688411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2220 + ... + 2881.

It is an arithmetic number, because the mean of its divisors is an integer number (423466).

2^1688431 is an apocalyptic number.

1688431 is a deficient number, since it is larger than the sum of its proper divisors (5433).

1688431 is an equidigital number, since it uses as much as digits as its factorization.

1688431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5432.

The product of its digits is 4608, while the sum is 31.

The square root of 1688431 is about 1299.3963983327. The cubic root of 1688431 is about 119.0769692484.

The spelling of 1688431 in words is "one million, six hundred eighty-eight thousand, four hundred thirty-one".