1686997 has 4 divisors (see below), whose sum is σ = 1816780. Its totient is φ = 1557216.

The previous prime is 1686983. The next prime is 1687009. The reversal of 1686997 is 7996861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7996861 = 619 ⋅12919.

It can be written as a sum of positive squares in 2 ways, for example, as 1110916 + 576081 = 1054^2 + 759^2 .

It is a cyclic number.

It is not a de Polignac number, because 1686997 - 2¹⁹ = 1162709 is a prime.

It is a Duffinian number.

1686997 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1686907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64872 + ... + 64897.

It is an arithmetic number, because the mean of its divisors is an integer number (454195).

2^1686997 is an apocalyptic number.

It is an amenable number.

1686997 is a deficient number, since it is larger than the sum of its proper divisors (129783).

1686997 is a wasteful number, since it uses less digits than its factorization.

1686997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129782.

The product of its digits is 163296, while the sum is 46.

The square root of 1686997 is about 1298.8444864571. The cubic root of 1686997 is about 119.0432486446.

The spelling of 1686997 in words is "one million, six hundred eighty-six thousand, nine hundred ninety-seven".