261665165054523 has 32 divisors (see below), whose sum is σ = 370613073499200. Its totient is φ = 163647575285760.

The previous prime is 261665165054521. The next prime is 261665165054563. The reversal of 261665165054523 is 325450561566162.

It is not a de Polignac number, because 261665165054523 - 2¹ = 261665165054521 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261665165054521) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 42637363 + ... + 48386723.

It is an arithmetic number, because the mean of its divisors is an integer number (11581658546850).

Almost surely, 2^{261665165054523} is an apocalyptic number.

261665165054523 is a deficient number, since it is larger than the sum of its proper divisors (108947908444677).

261665165054523 is a wasteful number, since it uses less digits than its factorization.

261665165054523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5752287.

The product of its (nonzero) digits is 38880000, while the sum is 57.

The spelling of 261665165054523 in words is "two hundred sixty-one trillion, six hundred sixty-five billion, one hundred sixty-five million, fifty-four thousand, five hundred twenty-three".