261388225180128 has 24 divisors (see below), whose sum is σ = 686144091098088. Its totient is φ = 87129408393344.

The previous prime is 261388225180067. The next prime is 261388225180157. The reversal of 261388225180128 is 821081522883162.

It is a tau number, because it is divible by the number of its divisors (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1361397006051 + ... + 1361397006242.

It is an arithmetic number, because the mean of its divisors is an integer number (28589337129087).

Almost surely, 2^{261388225180128} is an apocalyptic number.

It is an amenable number.

261388225180128 is an abundant number, since it is smaller than the sum of its proper divisors (424755865917960).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261388225180128 is a wasteful number, since it uses less digits than its factorization.

261388225180128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2722794012306 (or 2722794012298 counting only the distinct ones).

The product of its (nonzero) digits is 5898240, while the sum is 57.

The spelling of 261388225180128 in words is "two hundred sixty-one trillion, three hundred eighty-eight billion, two hundred twenty-five million, one hundred eighty thousand, one hundred twenty-eight".