168943436021 has 2 divisors, whose sum is σ = 168943436022. Its totient is φ = 168943436020.

The previous prime is 168943435993. The next prime is 168943436059. The reversal of 168943436021 is 120634349861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 85431105796 + 83512330225 = 292286^2 + 288985^2 .

It is a cyclic number.

It is not a de Polignac number, because 168943436021 - 2¹⁴ = 168943419637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (168943438021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84471718010 + 84471718011.

It is an arithmetic number, because the mean of its divisors is an integer number (84471718011).

Almost surely, 2^168943436021 is an apocalyptic number.

It is an amenable number.

168943436021 is a deficient number, since it is larger than the sum of its proper divisors (1).

168943436021 is an equidigital number, since it uses as much as digits as its factorization.

168943436021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 746496, while the sum is 47.

The spelling of 168943436021 in words is "one hundred sixty-eight billion, nine hundred forty-three million, four hundred thirty-six thousand, twenty-one".