261535171051550 has 48 divisors (see below), whose sum is σ = 533934335336832. Its totient is φ = 94520240258400.

The previous prime is 261535171051543. The next prime is 261535171051559. The reversal of 261535171051550 is 55150171535162.

It is a junction number, because it is equal to n+sod(n) for n = 261535171051495 and 261535171051504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261535171051559) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1458556034 + ... + 1458735333.

It is an arithmetic number, because the mean of its divisors is an integer number (11123631986184).

Almost surely, 2^{261535171051550} is an apocalyptic number.

261535171051550 is an abundant number, since it is smaller than the sum of its proper divisors (272399164285282).

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

261535171051550 is a wasteful number, since it uses less digits than its factorization.

261535171051550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2917291553 (or 2917291548 counting only the distinct ones).

The product of its (nonzero) digits is 787500, while the sum is 47.

The spelling of 261535171051550 in words is "two hundred sixty-one trillion, five hundred thirty-five billion, one hundred seventy-one million, fifty-one thousand, five hundred fifty".