261657075256605 has 24 divisors (see below), whose sum is σ = 518330206223232. Its totient is φ = 119614662974304.

The previous prime is 261657075256571. The next prime is 261657075256607. The reversal of 261657075256605 is 506652570756162.

261657075256605 is a `hidden beast` number, since 2 + 6 + 1 + 6 + 570 + 7 + 5 + 2 + 56 + 6 + 0 + 5 = 666.

It is not a de Polignac number, because 261657075256605 - 2⁷ = 261657075256477 is a prime.

It is a super-2 number, since 2×261657075256605² (a number of 30 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261657075256607) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 415328690569 + ... + 415328691198.

It is an arithmetic number, because the mean of its divisors is an integer number (21597091925968).

Almost surely, 2^{261657075256605} is an apocalyptic number.

It is an amenable number.

261657075256605 is a deficient number, since it is larger than the sum of its proper divisors (256673130966627).

261657075256605 is a wasteful number, since it uses less digits than its factorization.

261657075256605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 830657381785 (or 830657381782 counting only the distinct ones).

The product of its (nonzero) digits is 158760000, while the sum is 63.

The spelling of 261657075256605 in words is "two hundred sixty-one trillion, six hundred fifty-seven billion, seventy-five million, two hundred fifty-six thousand, six hundred five".