1686431 has 4 divisors (see below), whose sum is σ = 1740864. Its totient is φ = 1632000.

The previous prime is 1686409. The next prime is 1686439. The reversal of 1686431 is 1346861.

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

It is a cyclic number.

It is not a de Polignac number, because 1686431 - 2⁶ = 1686367 is a prime.

It is a super-2 number, since 2×1686431² = 5688099035522, 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 = 1686394 and 1686403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1686439) 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, 27170 + ... + 27231.

It is an arithmetic number, because the mean of its divisors is an integer number (435216).

2^1686431 is an apocalyptic number.

1686431 is a deficient number, since it is larger than the sum of its proper divisors (54433).

1686431 is an equidigital number, since it uses as much as digits as its factorization.

1686431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54432.

The product of its digits is 3456, while the sum is 29.

The square root of 1686431 is about 1298.6265822014. The cubic root of 1686431 is about 119.0299338580.

The spelling of 1686431 in words is "one million, six hundred eighty-six thousand, four hundred thirty-one".