261809700120 has 320 divisors, whose sum is σ = 920343695040. Its totient is φ = 66626841600.

The previous prime is 261809700109. The next prime is 261809700161. The reversal of 261809700120 is 21007908162.

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 polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 34349910 + ... + 34357530.

It is an arithmetic number, because the mean of its divisors is an integer number (2876074047).

Almost surely, 2^261809700120 is an apocalyptic number.

261809700120 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 261809700120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (460171847520).

261809700120 is an abundant number, since it is smaller than the sum of its proper divisors (658533994920).

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

261809700120 is a wasteful number, since it uses less digits than its factorization.

261809700120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8128 (or 8115 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The spelling of 261809700120 in words is "two hundred sixty-one billion, eight hundred nine million, seven hundred thousand, one hundred twenty".