261761310720 has 2016 divisors, whose sum is σ = 1230275749248. Its totient is φ = 51980009472.

The previous prime is 261761310659. The next prime is 261761310761. The reversal of 261761310720 is 27013167162.

It is a happy number.

261761310720 is a `hidden beast` number, since 2 + 6 + 1 + 7 + 613 + 10 + 7 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (2016).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

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 143 ways as a sum of consecutive naturals, for example, 15397724152 + ... + 15397724168.

It is an arithmetic number, because the mean of its divisors is an integer number (610255828).

Almost surely, 2^261761310720 is an apocalyptic number.

261761310720 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 261761310720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (615137874624).

261761310720 is an abundant number, since it is smaller than the sum of its proper divisors (968514438528).

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

261761310720 is an equidigital number, since it uses as much as digits as its factorization.

261761310720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

Adding to 261761310720 its reverse (27013167162), we get a palindrome (288774477882).

The spelling of 261761310720 in words is "two hundred sixty-one billion, seven hundred sixty-one million, three hundred ten thousand, seven hundred twenty".