261055321 has 2 divisors, whose sum is σ = 261055322. Its totient is φ = 261055320.

The previous prime is 261055271. The next prime is 261055337. The reversal of 261055321 is 123550162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 244766025 + 16289296 = 15645^2 + 4036^2 .

It is a cyclic number.

It is not a de Polignac number, because 261055321 - 2²⁷ = 126837593 is a prime.

It is not a weakly prime, because it can be changed into another prime (261055351) 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, 130527660 + 130527661.

It is an arithmetic number, because the mean of its divisors is an integer number (130527661).

Almost surely, 2^261055321 is an apocalyptic number.

It is an amenable number.

261055321 is a deficient number, since it is larger than the sum of its proper divisors (1).

261055321 is an equidigital number, since it uses as much as digits as its factorization.

261055321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 261055321 is about 16157.2064726549. The cubic root of 261055321 is about 639.1128014531.

The spelling of 261055321 in words is "two hundred sixty-one million, fifty-five thousand, three hundred twenty-one".