168823981 has 2 divisors, whose sum is σ = 168823982. Its totient is φ = 168823980.

The previous prime is 168823969. The next prime is 168823997. The reversal of 168823981 is 189328861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 167702500 + 1121481 = 12950^2 + 1059^2 .

It is a cyclic number.

It is not a de Polignac number, because 168823981 - 2¹³ = 168815789 is a prime.

It is a super-2 number, since 2×168823981² = 57003073121376722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (168823931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84411990 + 84411991.

It is an arithmetic number, because the mean of its divisors is an integer number (84411991).

Almost surely, 2^168823981 is an apocalyptic number.

It is an amenable number.

168823981 is a deficient number, since it is larger than the sum of its proper divisors (1).

168823981 is an equidigital number, since it uses as much as digits as its factorization.

168823981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 165888, while the sum is 46.

The square root of 168823981 is about 12993.2282747591. The cubic root of 168823981 is about 552.6854680598.

The spelling of 168823981 in words is "one hundred sixty-eight million, eight hundred twenty-three thousand, nine hundred eighty-one".