1689381 has 12 divisors (see below), whose sum is σ = 2451852. Its totient is φ = 1120896.

The previous prime is 1689379. The next prime is 1689397. The reversal of 1689381 is 1839861.

It can be written as a sum of positive squares in 2 ways, for example, as 285156 + 1404225 = 534^2 + 1185^2 .

It is not a de Polignac number, because 1689381 - 2¹ = 1689379 is a prime.

It is a super-2 number, since 2×1689381² = 5708016326322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1689781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2755 + ... + 3311.

It is an arithmetic number, because the mean of its divisors is an integer number (204321).

2^1689381 is an apocalyptic number.

It is an amenable number.

1689381 is a deficient number, since it is larger than the sum of its proper divisors (762471).

1689381 is a wasteful number, since it uses less digits than its factorization.

1689381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 900 (or 897 counting only the distinct ones).

The product of its digits is 10368, while the sum is 36.

The square root of 1689381 is about 1299.7619012727. The cubic root of 1689381 is about 119.0992980478.

The spelling of 1689381 in words is "one million, six hundred eighty-nine thousand, three hundred eighty-one".