168416921 has 2 divisors, whose sum is σ = 168416922. Its totient is φ = 168416920.

The previous prime is 168416903. The next prime is 168416923. The reversal of 168416921 is 129614861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 113656921 + 54760000 = 10661^2 + 7400^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-168416921 is a prime.

Together with 168416923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (168416923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84208460 + 84208461.

It is an arithmetic number, because the mean of its divisors is an integer number (84208461).

Almost surely, 2^168416921 is an apocalyptic number.

It is an amenable number.

168416921 is a deficient number, since it is larger than the sum of its proper divisors (1).

168416921 is an equidigital number, since it uses as much as digits as its factorization.

168416921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 38.

The square root of 168416921 is about 12977.5545076875. The cubic root of 168416921 is about 552.2409079821.

The spelling of 168416921 in words is "one hundred sixty-eight million, four hundred sixteen thousand, nine hundred twenty-one".