261280000000 has 384 divisors, whose sum is σ = 691029480960. Its totient is φ = 98560000000.

The previous prime is 261279999997. The next prime is 261280000001. The reversal of 261280000000 is 82162.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (261280000001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3679999965 + ... + 3680000035.

It is an arithmetic number, because the mean of its divisors is an integer number (1799555940).

Almost surely, 2^261280000000 is an apocalyptic number.

261280000000 is a gapful number since it is divisible by the number (20) 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 261280000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (345514740480).

261280000000 is an abundant number, since it is smaller than the sum of its proper divisors (429749480960).

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

261280000000 is an frugal number, since it uses more digits than its factorization.

261280000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 261280000000 its reverse (82162), we get a palindrome (261280082162).

The spelling of 261280000000 in words is "two hundred sixty-one billion, two hundred eighty million", and thus it is an aban number.