261510891180 has 384 divisors, whose sum is σ = 925535600640. Its totient is φ = 53591746560.

The previous prime is 261510891163. The next prime is 261510891203. The reversal of 261510891180 is 81198015162.

261510891180 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 (42).

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 127 ways as a sum of consecutive naturals, for example, 266032969 + ... + 266033951.

It is an arithmetic number, because the mean of its divisors is an integer number (2410248960).

Almost surely, 2^261510891180 is an apocalyptic number.

261510891180 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 261510891180, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (462767800320).

261510891180 is an abundant number, since it is smaller than the sum of its proper divisors (664024709460).

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

261510891180 is a wasteful number, since it uses less digits than its factorization.

261510891180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1749 (or 1747 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 42.

The spelling of 261510891180 in words is "two hundred sixty-one billion, five hundred ten million, eight hundred ninety-one thousand, one hundred eighty".