166643942401 has 2 divisors, whose sum is σ = 166643942402. Its totient is φ = 166643942400.

The previous prime is 166643942369. The next prime is 166643942417. The reversal of 166643942401 is 104249346661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 137011762801 + 29632179600 = 370151^2 + 172140^2 .

It is a cyclic number.

It is not a de Polignac number, because 166643942401 - 2⁵ = 166643942369 is a prime.

It is not a weakly prime, because it can be changed into another prime (166643942431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83321971200 + 83321971201.

It is an arithmetic number, because the mean of its divisors is an integer number (83321971201).

Almost surely, 2^166643942401 is an apocalyptic number.

It is an amenable number.

166643942401 is a deficient number, since it is larger than the sum of its proper divisors (1).

166643942401 is an equidigital number, since it uses as much as digits as its factorization.

166643942401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 746496, while the sum is 46.

The spelling of 166643942401 in words is "one hundred sixty-six billion, six hundred forty-three million, nine hundred forty-two thousand, four hundred one".