261535762553605 has 8 divisors (see below), whose sum is σ = 313843238005752. Its totient is φ = 209228394748608.

The previous prime is 261535762553603. The next prime is 261535762553609. The reversal of 261535762553605 is 506355267535162.

It can be written as a sum of positive squares in 4 ways, for example, as 130957102435201 + 130578660118404 = 11443649^2 + 11427102^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261535762553605 - 2¹ = 261535762553603 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 (261535762553603) 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, 21466582 + ... + 31366951.

It is an arithmetic number, because the mean of its divisors is an integer number (39230404750719).

Almost surely, 2^{261535762553605} is an apocalyptic number.

It is an amenable number.

261535762553605 is a deficient number, since it is larger than the sum of its proper divisors (52307475452147).

261535762553605 is an equidigital number, since it uses as much as digits as its factorization.

261535762553605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53823575.

The product of its (nonzero) digits is 170100000, while the sum is 61.

The spelling of 261535762553605 in words is "two hundred sixty-one trillion, five hundred thirty-five billion, seven hundred sixty-two million, five hundred fifty-three thousand, six hundred five".