1686644 has 6 divisors (see below), whose sum is σ = 2951634. Its totient is φ = 843320.

The previous prime is 1686637. The next prime is 1686647. The reversal of 1686644 is 4466861.

It can be written as a sum of positive squares in only one way, i.e., 1350244 + 336400 = 1162^2 + 580^2 .

It is a super-3 number, since 3×1686644³ = 14394332548421333952, which contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1686647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210827 + ... + 210834.

It is an arithmetic number, because the mean of its divisors is an integer number (491939).

2^1686644 is an apocalyptic number.

It is an amenable number.

1686644 is a deficient number, since it is larger than the sum of its proper divisors (1264990).

1686644 is a wasteful number, since it uses less digits than its factorization.

1686644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421665 (or 421663 counting only the distinct ones).

The product of its digits is 27648, while the sum is 35.

The square root of 1686644 is about 1298.7085893302. The cubic root of 1686644 is about 119.0349448958.

The spelling of 1686644 in words is "one million, six hundred eighty-six thousand, six hundred forty-four".