1686816 has 36 divisors (see below), whose sum is σ = 4797702. Its totient is φ = 562176.

The previous prime is 1686779. The next prime is 1686823. The reversal of 1686816 is 6186861.

It can be written as a sum of positive squares in only one way, i.e., 1040400 + 646416 = 1020^2 + 804^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2641 + ... + 3216.

2^1686816 is an apocalyptic number.

1686816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1686816 is an abundant number, since it is smaller than the sum of its proper divisors (3110886).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1686816 is a wasteful number, since it uses less digits than its factorization.

1686816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5873 (or 5862 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 1686816 is about 1298.7748072703. The cubic root of 1686816 is about 119.0389910598.

The spelling of 1686816 in words is "one million, six hundred eighty-six thousand, eight hundred sixteen".