261591205837 has 16 divisors (see below), whose sum is σ = 287060070528. Its totient is φ = 236887110720.

The previous prime is 261591205703. The next prime is 261591205849. The reversal of 261591205837 is 738502195162.

261591205837 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 261591205837 - 2¹¹ = 261591203789 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 (261591205037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9606912 + ... + 9634102.

It is an arithmetic number, because the mean of its divisors is an integer number (17941254408).

Almost surely, 2^261591205837 is an apocalyptic number.

It is an amenable number.

261591205837 is a deficient number, since it is larger than the sum of its proper divisors (25468864691).

261591205837 is a wasteful number, since it uses less digits than its factorization.

261591205837 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41220.

The product of its (nonzero) digits is 907200, while the sum is 49.

The spelling of 261591205837 in words is "two hundred sixty-one billion, five hundred ninety-one million, two hundred five thousand, eight hundred thirty-seven".