261906665852173 has 2 divisors, whose sum is σ = 261906665852174. Its totient is φ = 261906665852172.

The previous prime is 261906665852093. The next prime is 261906665852297. The reversal of 261906665852173 is 371258566609162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 261559524531204 + 347141320969 = 16172802^2 + 589187^2 .

It is a cyclic number.

It is not a de Polignac number, because 261906665852173 - 2¹⁷ = 261906665721101 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 261906665852099 and 261906665852108.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261906665852473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130953332926086 + 130953332926087.

It is an arithmetic number, because the mean of its divisors is an integer number (130953332926087).

Almost surely, 2^{261906665852173} is an apocalyptic number.

It is an amenable number.

261906665852173 is a deficient number, since it is larger than the sum of its proper divisors (1).

261906665852173 is an equidigital number, since it uses as much as digits as its factorization.

261906665852173 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 195955200, while the sum is 67.

The spelling of 261906665852173 in words is "two hundred sixty-one trillion, nine hundred six billion, six hundred sixty-five million, eight hundred fifty-two thousand, one hundred seventy-three".