261513517 has 2 divisors, whose sum is σ = 261513518. Its totient is φ = 261513516.

The previous prime is 261513509. The next prime is 261513523. The reversal of 261513517 is 715315162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 247779081 + 13734436 = 15741^2 + 3706^2 .

It is a cyclic number.

It is not a de Polignac number, because 261513517 - 2³ = 261513509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261511517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130756758 + 130756759.

It is an arithmetic number, because the mean of its divisors is an integer number (130756759).

Almost surely, 2^261513517 is an apocalyptic number.

It is an amenable number.

261513517 is a deficient number, since it is larger than the sum of its proper divisors (1).

261513517 is an equidigital number, since it uses as much as digits as its factorization.

261513517 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6300, while the sum is 31.

The square root of 261513517 is about 16171.3795639086. The cubic root of 261513517 is about 639.4864997273.

Adding to 261513517 its reverse (715315162), we get a palindrome (976828679).

The spelling of 261513517 in words is "two hundred sixty-one million, five hundred thirteen thousand, five hundred seventeen".