261665536235 has 16 divisors (see below), whose sum is σ = 327673774656. Its totient is φ = 200216953728.

The previous prime is 261665536211. The next prime is 261665536243. The reversal of 261665536235 is 532635566162.

It is a cyclic number.

It is not a de Polignac number, because 261665536235 - 2²⁰ = 261664487659 is a prime.

It is a super-3 number, since 3×261665536235³ (a number of 35 digits) contains 333 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1744637 + ... + 1888673.

It is an arithmetic number, because the mean of its divisors is an integer number (20479610916).

Almost surely, 2^261665536235 is an apocalyptic number.

261665536235 is a deficient number, since it is larger than the sum of its proper divisors (66008238421).

261665536235 is a wasteful number, since it uses less digits than its factorization.

261665536235 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159862.

The product of its digits is 5832000, while the sum is 50.

The spelling of 261665536235 in words is "two hundred sixty-one billion, six hundred sixty-five million, five hundred thirty-six thousand, two hundred thirty-five".