261009264768 has 128 divisors (see below), whose sum is σ = 797668560000. Its totient is φ = 74073464832.

The previous prime is 261009264757. The next prime is 261009264781. The reversal of 261009264768 is 867462900162.

It is a tau number, because it is divible by the number of its divisors (128).

It is a self number, because there is not a number n which added to its sum of digits gives 261009264768.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74668 + ... + 726356.

It is an arithmetic number, because the mean of its divisors is an integer number (6231785625).

Almost surely, 2^261009264768 is an apocalyptic number.

261009264768 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261009264768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (398834280000).

261009264768 is an abundant number, since it is smaller than the sum of its proper divisors (536659295232).

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

261009264768 is a wasteful number, since it uses less digits than its factorization.

261009264768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 651862 (or 651850 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 51.

The spelling of 261009264768 in words is "two hundred sixty-one billion, nine million, two hundred sixty-four thousand, seven hundred sixty-eight".