168691 has 4 divisors (see below), whose sum is σ = 178632. Its totient is φ = 158752.

The previous prime is 168677. The next prime is 168697. The reversal of 168691 is 196861.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 196861 = 7 ⋅28123.

It is a cyclic number.

It is not a de Polignac number, because 168691 - 2¹¹ = 166643 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (168697) 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, 4945 + ... + 4978.

It is an arithmetic number, because the mean of its divisors is an integer number (44658).

2¹⁶⁸⁶⁹¹ is an apocalyptic number.

168691 is a deficient number, since it is larger than the sum of its proper divisors (9941).

168691 is an equidigital number, since it uses as much as digits as its factorization.

168691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9940.

The product of its digits is 2592, while the sum is 31.

The square root of 168691 is about 410.7200993377. The cubic root of 168691 is about 55.2540314961.

The spelling of 168691 in words is "one hundred sixty-eight thousand, six hundred ninety-one".