168846721 has 2 divisors, whose sum is σ = 168846722. Its totient is φ = 168846720.

The previous prime is 168846707. The next prime is 168846751. The reversal of 168846721 is 127648861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 166410000 + 2436721 = 12900^2 + 1561^2 .

It is an emirp because it is prime and its reverse (127648861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 168846721 - 2⁷ = 168846593 is a prime.

It is not a weakly prime, because it can be changed into another prime (168846751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84423360 + 84423361.

It is an arithmetic number, because the mean of its divisors is an integer number (84423361).

Almost surely, 2^168846721 is an apocalyptic number.

It is an amenable number.

168846721 is a deficient number, since it is larger than the sum of its proper divisors (1).

168846721 is an equidigital number, since it uses as much as digits as its factorization.

168846721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129024, while the sum is 43.

The square root of 168846721 is about 12994.1033165048. The cubic root of 168846721 is about 552.7102818791.

The spelling of 168846721 in words is "one hundred sixty-eight million, eight hundred forty-six thousand, seven hundred twenty-one".