261530189 has 2 divisors, whose sum is σ = 261530190. Its totient is φ = 261530188.

The previous prime is 261530179. The next prime is 261530237. The reversal of 261530189 is 981035162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162129289 + 99400900 = 12733^2 + 9970^2 .

It is a cyclic number.

It is not a de Polignac number, because 261530189 - 2⁴ = 261530173 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261530179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130765094 + 130765095.

It is an arithmetic number, because the mean of its divisors is an integer number (130765095).

Almost surely, 2^261530189 is an apocalyptic number.

It is an amenable number.

261530189 is a deficient number, since it is larger than the sum of its proper divisors (1).

261530189 is an equidigital number, since it uses as much as digits as its factorization.

261530189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 35.

The square root of 261530189 is about 16171.8950342871. The cubic root of 261530189 is about 639.5000889451.

The spelling of 261530189 in words is "two hundred sixty-one million, five hundred thirty thousand, one hundred eighty-nine".