1686481 has 4 divisors (see below), whose sum is σ = 1690432. Its totient is φ = 1682532.

The previous prime is 1686479. The next prime is 1686491. The reversal of 1686481 is 1846861.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1686481 - 2¹ = 1686479 is a prime.

It is a super-2 number, since 2×1686481² = 5688436326722, which contains 22 as substring.

It is a Duffinian number.

1686481 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1686491) 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, 1245 + ... + 2218.

It is an arithmetic number, because the mean of its divisors is an integer number (422608).

2^1686481 is an apocalyptic number.

It is an amenable number.

1686481 is a deficient number, since it is larger than the sum of its proper divisors (3951).

1686481 is an equidigital number, since it uses as much as digits as its factorization.

1686481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3950.

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

The square root of 1686481 is about 1298.6458331662. The cubic root of 1686481 is about 119.0311101958.

The spelling of 1686481 in words is "one million, six hundred eighty-six thousand, four hundred eighty-one".