168893821 has 2 divisors, whose sum is σ = 168893822. Its totient is φ = 168893820.

The previous prime is 168893783. The next prime is 168893843. The reversal of 168893821 is 128398861.

168893821 = 9189² + 9190².

168893821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 84456100 + 84437721 = 9190^2 + 9189^2 .

It is an emirp because it is prime and its reverse (128398861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 168893821 - 2⁷ = 168893693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (168893321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84446910 + 84446911.

It is an arithmetic number, because the mean of its divisors is an integer number (84446911).

Almost surely, 2^168893821 is an apocalyptic number.

168893821 is the 9190-th centered square number.

It is an amenable number.

168893821 is a deficient number, since it is larger than the sum of its proper divisors (1).

168893821 is an equidigital number, since it uses as much as digits as its factorization.

168893821 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 168893821 is about 12995.9155506644. The cubic root of 168893821 is about 552.7616701716.

The spelling of 168893821 in words is "one hundred sixty-eight million, eight hundred ninety-three thousand, eight hundred twenty-one".