261305069 has 2 divisors, whose sum is σ = 261305070. Its totient is φ = 261305068.

The previous prime is 261305039. The next prime is 261305071. The reversal of 261305069 is 960503162.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 261242569 + 62500 = 16163^2 + 250^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261305069 is a prime.

It is a super-2 number, since 2×261305069² = 136560678170189522, which contains 22 as substring.

Together with 261305071, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261305039) 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, 130652534 + 130652535.

It is an arithmetic number, because the mean of its divisors is an integer number (130652535).

Almost surely, 2^261305069 is an apocalyptic number.

It is an amenable number.

261305069 is a deficient number, since it is larger than the sum of its proper divisors (1).

261305069 is an equidigital number, since it uses as much as digits as its factorization.

261305069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9720, while the sum is 32.

The square root of 261305069 is about 16164.9333125751. The cubic root of 261305069 is about 639.3165466071.

The spelling of 261305069 in words is "two hundred sixty-one million, three hundred five thousand, sixty-nine".