173985351365921 has 2 divisors, whose sum is σ = 173985351365922. Its totient is φ = 173985351365920.

The previous prime is 173985351365869. The next prime is 173985351365963. The reversal of 173985351365921 is 129563153589371.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 165511081042321 + 8474270323600 = 12865111^2 + 2911060^2 .

It is a cyclic number.

It is not a de Polignac number, because 173985351365921 - 2⁶ = 173985351365857 is a prime.

It is not a weakly prime, because it can be changed into another prime (173985351365321) 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, 86992675682960 + 86992675682961.

It is an arithmetic number, because the mean of its divisors is an integer number (86992675682961).

Almost surely, 2^{173985351365921} is an apocalyptic number.

It is an amenable number.

173985351365921 is a deficient number, since it is larger than the sum of its proper divisors (1).

173985351365921 is an equidigital number, since it uses as much as digits as its factorization.

173985351365921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 183708000, while the sum is 68.

The spelling of 173985351365921 in words is "one hundred seventy-three trillion, nine hundred eighty-five billion, three hundred fifty-one million, three hundred sixty-five thousand, nine hundred twenty-one".