1681693 has 4 divisors (see below), whose sum is σ = 1811068. Its totient is φ = 1552320.

The previous prime is 1681679. The next prime is 1681703. The reversal of 1681693 is 3961861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3961861 = 19 ⋅208519.

It can be written as a sum of positive squares in 2 ways, for example, as 675684 + 1006009 = 822^2 + 1003^2 .

It is a cyclic number.

It is not a de Polignac number, because 1681693 - 2⁵ = 1681661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1681193) 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 3 ways as a sum of consecutive naturals, for example, 64668 + ... + 64693.

It is an arithmetic number, because the mean of its divisors is an integer number (452767).

2^1681693 is an apocalyptic number.

1681693 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1681693 is a deficient number, since it is larger than the sum of its proper divisors (129375).

1681693 is a wasteful number, since it uses less digits than its factorization.

1681693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129374.

The product of its digits is 7776, while the sum is 34.

The square root of 1681693 is about 1296.8010641575. The cubic root of 1681693 is about 118.9183584261.

The spelling of 1681693 in words is "one million, six hundred eighty-one thousand, six hundred ninety-three".