261545344705125 has 96 divisors (see below), whose sum is σ = 517326823724256. Its totient is φ = 126331335936000.

The previous prime is 261545344705093. The next prime is 261545344705129. The reversal of 261545344705125 is 521507443545162.

261545344705125 is a `hidden beast` number, since 2 + 6 + 1 + 5 + 4 + 53 + 4 + 4 + 70 + 512 + 5 = 666.

It can be written as a sum of positive squares in 16 ways, for example, as 126917731413729 + 134627613291396 = 11265777^2 + 11602914^2 .

It is not a de Polignac number, because 261545344705125 - 2⁵ = 261545344705093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261545344705129) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 167936596 + ... + 169486845.

It is an arithmetic number, because the mean of its divisors is an integer number (5388821080461).

Almost surely, 2^{261545344705125} is an apocalyptic number.

261545344705125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261545344705125 is a deficient number, since it is larger than the sum of its proper divisors (255781479019131).

261545344705125 is a wasteful number, since it uses less digits than its factorization.

261545344705125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337423528 (or 337423515 counting only the distinct ones).

The product of its (nonzero) digits is 20160000, while the sum is 54.

The spelling of 261545344705125 in words is "two hundred sixty-one trillion, five hundred forty-five billion, three hundred forty-four million, seven hundred five thousand, one hundred twenty-five".