261635513 has 2 divisors, whose sum is σ = 261635514. Its totient is φ = 261635512.

The previous prime is 261635501. The next prime is 261635519. The reversal of 261635513 is 315536162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 252587449 + 9048064 = 15893^2 + 3008^2 .

It is a cyclic number.

It is not a de Polignac number, because 261635513 - 2¹⁴ = 261619129 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261635513.

It is not a weakly prime, because it can be changed into another prime (261635519) 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, 130817756 + 130817757.

It is an arithmetic number, because the mean of its divisors is an integer number (130817757).

Almost surely, 2^261635513 is an apocalyptic number.

It is an amenable number.

261635513 is a deficient number, since it is larger than the sum of its proper divisors (1).

261635513 is an equidigital number, since it uses as much as digits as its factorization.

261635513 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16200, while the sum is 32.

The square root of 261635513 is about 16175.1510966668. The cubic root of 261635513 is about 639.5859243737.

The spelling of 261635513 in words is "two hundred sixty-one million, six hundred thirty-five thousand, five hundred thirteen".