261294508081152 has 1728 divisors, whose sum is σ = 1001434913740800. Its totient is φ = 66672006266880.

The previous prime is 261294508081091. The next prime is 261294508081193. The reversal of 261294508081152 is 251180805492162.

It is a happy number.

261294508081152 is a `hidden beast` number, since 2 + 6 + 1 + 2 + 9 + 4 + 508 + 0 + 81 + 1 + 52 = 666.

It is a tau number, because it is divible by the number of its divisors (1728).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 69883525299 + ... + 69883529037.

It is an arithmetic number, because the mean of its divisors is an integer number (579534093600).

Almost surely, 2^{261294508081152} 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 261294508081152, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (500717456870400).

261294508081152 is an abundant number, since it is smaller than the sum of its proper divisors (740140405659648).

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

261294508081152 is an equidigital number, since it uses as much as digits as its factorization.

261294508081152 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3840 (or 3795 counting only the distinct ones).

The product of its (nonzero) digits is 2764800, while the sum is 54.

The spelling of 261294508081152 in words is "two hundred sixty-one trillion, two hundred ninety-four billion, five hundred eight million, eighty-one thousand, one hundred fifty-two".