168986891 has 4 divisors (see below), whose sum is σ = 169012992. Its totient is φ = 168960792.

The previous prime is 168986869. The next prime is 168986903. The reversal of 168986891 is 198689861.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 198689861 = 149 ⋅1333489.

It is a cyclic number.

It is not a de Polignac number, because 168986891 - 2²⁶ = 101878027 is a prime.

168986891 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (168986821) 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, 4805 + ... + 19001.

It is an arithmetic number, because the mean of its divisors is an integer number (42253248).

Almost surely, 2^168986891 is an apocalyptic number.

168986891 is a deficient number, since it is larger than the sum of its proper divisors (26101).

168986891 is a wasteful number, since it uses less digits than its factorization.

168986891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26100.

The product of its digits is 1492992, while the sum is 56.

The square root of 168986891 is about 12999.4957979146. The cubic root of 168986891 is about 552.8631857894.

The spelling of 168986891 in words is "one hundred sixty-eight million, nine hundred eighty-six thousand, eight hundred ninety-one".