261206559 has 8 divisors (see below), whose sum is σ = 386972720. Its totient is φ = 174137688.

The previous prime is 261206549. The next prime is 261206563. The reversal of 261206559 is 955602162.

It is not a de Polignac number, because 261206559 - 2⁸ = 261206303 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 (261206549) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4837132 + ... + 4837185.

It is an arithmetic number, because the mean of its divisors is an integer number (48371590).

Almost surely, 2^261206559 is an apocalyptic number.

261206559 is a deficient number, since it is larger than the sum of its proper divisors (125766161).

261206559 is an equidigital number, since it uses as much as digits as its factorization.

261206559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9674326 (or 9674320 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 261206559 is about 16161.8859976180. The cubic root of 261206559 is about 639.2361973700.

The spelling of 261206559 in words is "two hundred sixty-one million, two hundred six thousand, five hundred fifty-nine".