261166023165 has 16 divisors (see below), whose sum is σ = 442445969088. Its totient is φ = 131095101696.

The previous prime is 261166023161. The next prime is 261166023197. The reversal of 261166023165 is 561320661162.

It is not a de Polignac number, because 261166023165 - 2² = 261166023161 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261166023161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 512089987 + ... + 512090496.

It is an arithmetic number, because the mean of its divisors is an integer number (27652873068).

Almost surely, 2^261166023165 is an apocalyptic number.

It is an amenable number.

261166023165 is a deficient number, since it is larger than the sum of its proper divisors (181279945923).

261166023165 is a wasteful number, since it uses less digits than its factorization.

261166023165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1024180508.

The product of its (nonzero) digits is 77760, while the sum is 39.

The spelling of 261166023165 in words is "two hundred sixty-one billion, one hundred sixty-six million, twenty-three thousand, one hundred sixty-five".