261431265021767 has 4 divisors (see below), whose sum is σ = 261445002167856. Its totient is φ = 261417527875680.

The previous prime is 261431265021709. The next prime is 261431265021769. The reversal of 261431265021767 is 767120562134162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261431265021767 - 2²⁸ = 261430996586311 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 (261431265021769) 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 3 ways as a sum of consecutive naturals, for example, 6868544498 + ... + 6868582559.

It is an arithmetic number, because the mean of its divisors is an integer number (65361250541964).

Almost surely, 2^{261431265021767} is an apocalyptic number.

261431265021767 is a deficient number, since it is larger than the sum of its proper divisors (13737146089).

261431265021767 is a wasteful number, since it uses less digits than its factorization.

261431265021767 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13737146088.

The product of its (nonzero) digits is 5080320, while the sum is 53.

The spelling of 261431265021767 in words is "two hundred sixty-one trillion, four hundred thirty-one billion, two hundred sixty-five million, twenty-one thousand, seven hundred sixty-seven".