166095494977721 has 2 divisors, whose sum is σ = 166095494977722. Its totient is φ = 166095494977720.

The previous prime is 166095494977663. The next prime is 166095494977739. The reversal of 166095494977721 is 127779494590661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 156286002073600 + 9809492904121 = 12501440^2 + 3132011^2 .

It is a cyclic number.

It is not a de Polignac number, because 166095494977721 - 2¹⁴ = 166095494961337 is a prime.

It is not a weakly prime, because it can be changed into another prime (166095494977781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83047747488860 + 83047747488861.

It is an arithmetic number, because the mean of its divisors is an integer number (83047747488861).

Almost surely, 2^{166095494977721} is an apocalyptic number.

It is an amenable number.

166095494977721 is a deficient number, since it is larger than the sum of its proper divisors (1).

166095494977721 is an equidigital number, since it uses as much as digits as its factorization.

166095494977721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440270720, while the sum is 77.

The spelling of 166095494977721 in words is "one hundred sixty-six trillion, ninety-five billion, four hundred ninety-four million, nine hundred seventy-seven thousand, seven hundred twenty-one".