261613255680 has 2464 divisors, whose sum is σ = 1237176668160. Its totient is φ = 51597803520.

The previous prime is 261613255613. The next prime is 261613255691. The reversal of 261613255680 is 86552316162.

261613255680 is a `hidden beast` number, since 2 + 6 + 1 + 6 + 13 + 2 + 556 + 80 = 666.

261613255680 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (45).

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 223 ways as a sum of consecutive naturals, for example, 8439137265 + ... + 8439137295.

Almost surely, 2^261613255680 is an apocalyptic number.

261613255680 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 261613255680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (618588334080).

261613255680 is an abundant number, since it is smaller than the sum of its proper divisors (975563412480).

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

261613255680 is a wasteful number, since it uses less digits than its factorization.

261613255680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117 (or 84 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The spelling of 261613255680 in words is "two hundred sixty-one billion, six hundred thirteen million, two hundred fifty-five thousand, six hundred eighty".