261019709 has 12 divisors (see below), whose sum is σ = 273648732. Its totient is φ = 248952000.

The previous prime is 261019699. The next prime is 261019741. The reversal of 261019709 is 907910162.

It can be written as a sum of positive squares in 2 ways, for example, as 148596100 + 112423609 = 12190^2 + 10603^2 .

It is not a de Polignac number, because 261019709 - 2¹⁶ = 260954173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261019789) 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 in 11 ways as a sum of consecutive naturals, for example, 317519 + ... + 318339.

It is an arithmetic number, because the mean of its divisors is an integer number (22804061).

Almost surely, 2^261019709 is an apocalyptic number.

It is an amenable number.

261019709 is a deficient number, since it is larger than the sum of its proper divisors (12629023).

261019709 is an equidigital number, since it uses as much as digits as its factorization.

261019709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1468 (or 1445 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 35.

The square root of 261019709 is about 16156.1043881253. The cubic root of 261019709 is about 639.0837384943.

The spelling of 261019709 in words is "two hundred sixty-one million, nineteen thousand, seven hundred nine".