261550874256 has 640 divisors, whose sum is σ = 863944704000. Its totient is φ = 67963392000.

The previous prime is 261550874251. The next prime is 261550874267. The reversal of 261550874256 is 652478055162.

It is a junction number, because it is equal to n+sod(n) for n = 261550874199 and 261550874208.

It is not an unprimeable number, because it can be changed into a prime (261550874251) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 606846361 + ... + 606846791.

It is an arithmetic number, because the mean of its divisors is an integer number (1349913600).

Almost surely, 2^261550874256 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261550874256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (431972352000).

261550874256 is an abundant number, since it is smaller than the sum of its proper divisors (602393829744).

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

261550874256 is a wasteful number, since it uses less digits than its factorization.

261550874256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 564 (or 544 counting only the distinct ones).

The product of its (nonzero) digits is 4032000, while the sum is 51.

The spelling of 261550874256 in words is "two hundred sixty-one billion, five hundred fifty million, eight hundred seventy-four thousand, two hundred fifty-six".