173121961 has 2 divisors, whose sum is σ = 173121962. Its totient is φ = 173121960.

The previous prime is 173121947. The next prime is 173121973. The reversal of 173121961 is 169121371.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 135373225 + 37748736 = 11635^2 + 6144^2 .

It is an emirp because it is prime and its reverse (169121371) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 173121961 - 2²³ = 164733353 is a prime.

It is not a weakly prime, because it can be changed into another prime (173121911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86560980 + 86560981.

It is an arithmetic number, because the mean of its divisors is an integer number (86560981).

Almost surely, 2^173121961 is an apocalyptic number.

It is an amenable number.

173121961 is a deficient number, since it is larger than the sum of its proper divisors (1).

173121961 is an equidigital number, since it uses as much as digits as its factorization.

173121961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2268, while the sum is 31.

The square root of 173121961 is about 13157.5818827017. The cubic root of 173121961 is about 557.3363737866.

The spelling of 173121961 in words is "one hundred seventy-three million, one hundred twenty-one thousand, nine hundred sixty-one".