261184878907 has 4 divisors (see below), whose sum is σ = 261572970040. Its totient is φ = 260796787776.

The previous prime is 261184878883. The next prime is 261184878949. The reversal of 261184878907 is 709878481162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 709878481162 = 2 ⋅354939240581.

It is a cyclic number.

It is not a de Polignac number, because 261184878907 - 2¹¹ = 261184876859 is a prime.

It is the 511063-rd Hogben number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261184878007) by changing a digit.

It is a nontrivial repunit in base 511062.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 194044557 + ... + 194045902.

It is an arithmetic number, because the mean of its divisors is an integer number (65393242510).

Almost surely, 2^261184878907 is an apocalyptic number.

261184878907 is a deficient number, since it is larger than the sum of its proper divisors (388091133).

261184878907 is an equidigital number, since it uses as much as digits as its factorization.

261184878907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 388091132.

The product of its (nonzero) digits is 10838016, while the sum is 61.

The spelling of 261184878907 in words is "two hundred sixty-one billion, one hundred eighty-four million, eight hundred seventy-eight thousand, nine hundred seven".