261665050554727 has 16 divisors (see below), whose sum is σ = 269261657008992. Its totient is φ = 254096085335040.

The previous prime is 261665050554709. The next prime is 261665050554827. The reversal of 261665050554727 is 727455050566162.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 261665050554727 - 2²³ = 261665042166119 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 (261665050554827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 639849823 + ... + 640258639.

It is an arithmetic number, because the mean of its divisors is an integer number (16828853563062).

Almost surely, 2^{261665050554727} is an apocalyptic number.

261665050554727 is a deficient number, since it is larger than the sum of its proper divisors (7596606454265).

261665050554727 is a wasteful number, since it uses less digits than its factorization.

261665050554727 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442578.

The product of its (nonzero) digits is 105840000, while the sum is 61.

The spelling of 261665050554727 in words is "two hundred sixty-one trillion, six hundred sixty-five billion, fifty million, five hundred fifty-four thousand, seven hundred twenty-seven".