261065173 has 2 divisors, whose sum is σ = 261065174. Its totient is φ = 261065172.

The previous prime is 261065153. The next prime is 261065179. The reversal of 261065173 is 371560162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 250683889 + 10381284 = 15833^2 + 3222^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261065173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261065179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130532586 + 130532587.

It is an arithmetic number, because the mean of its divisors is an integer number (130532587).

Almost surely, 2^261065173 is an apocalyptic number.

It is an amenable number.

261065173 is a deficient number, since it is larger than the sum of its proper divisors (1).

261065173 is an equidigital number, since it uses as much as digits as its factorization.

261065173 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 261065173 is about 16157.5113492146. The cubic root of 261065173 is about 639.1208412050.

The spelling of 261065173 in words is "two hundred sixty-one million, sixty-five thousand, one hundred seventy-three".