261885646701720 has 640 divisors, whose sum is σ = 893277629798400. Its totient is φ = 68810247926784.

The previous prime is 261885646701683. The next prime is 261885646701761. The reversal of 261885646701720 is 27107646588162.

261885646701720 is a `hidden beast` number, since 2 + 6 + 1 + 8 + 8 + 564 + 67 + 0 + 1 + 7 + 2 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 37632651601 + ... + 37632658559.

It is an arithmetic number, because the mean of its divisors is an integer number (1395746296560).

Almost surely, 2^{261885646701720} is an apocalyptic number.

261885646701720 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 261885646701720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (446638814899200).

261885646701720 is an abundant number, since it is smaller than the sum of its proper divisors (631391983096680).

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

261885646701720 is a wasteful number, since it uses less digits than its factorization.

261885646701720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7749 (or 7736 counting only the distinct ones).

The product of its (nonzero) digits is 54190080, while the sum is 63.

The spelling of 261885646701720 in words is "two hundred sixty-one trillion, eight hundred eighty-five billion, six hundred forty-six million, seven hundred one thousand, seven hundred twenty".