168744221 has 2 divisors, whose sum is σ = 168744222. Its totient is φ = 168744220.

The previous prime is 168744211. The next prime is 168744223. The reversal of 168744221 is 122447861.

168744221 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., 164121721 + 4622500 = 12811^2 + 2150^2 .

It is a cyclic number.

It is not a de Polignac number, because 168744221 - 2¹⁴ = 168727837 is a prime.

It is a super-2 number, since 2×168744221² = 56949224241793682, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 168744223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (168744223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84372110 + 84372111.

It is an arithmetic number, because the mean of its divisors is an integer number (84372111).

Almost surely, 2^168744221 is an apocalyptic number.

It is an amenable number.

168744221 is a deficient number, since it is larger than the sum of its proper divisors (1).

168744221 is an equidigital number, since it uses as much as digits as its factorization.

168744221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21504, while the sum is 35.

The square root of 168744221 is about 12990.1586210485. The cubic root of 168744221 is about 552.5984165706.

The spelling of 168744221 in words is "one hundred sixty-eight million, seven hundred forty-four thousand, two hundred twenty-one".