9865781280 has 144 divisors (see below), whose sum is σ = 34383533184. Its totient is φ = 2574881280.

The previous prime is 9865781267. The next prime is 9865781291. The reversal of 9865781280 is 821875689.

It is a tau number, because it is divible by the number of its divisors (144).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5206 + ... + 140565.

It is an arithmetic number, because the mean of its divisors is an integer number (238774536).

Almost surely, 2^9865781280 is an apocalyptic number.

9865781280 is a gapful number since it is divisible by the number (90) 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 9865781280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (17191766592).

9865781280 is an abundant number, since it is smaller than the sum of its proper divisors (24517751904).

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

9865781280 is a wasteful number, since it uses less digits than its factorization.

9865781280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145839 (or 145828 counting only the distinct ones).

The product of its (nonzero) digits is 1935360, while the sum is 54.

The square root of 9865781280 is about 99326.6393270204. The cubic root of 9865781280 is about 2144.7523928900.

The spelling of 9865781280 in words is "nine billion, eight hundred sixty-five million, seven hundred eighty-one thousand, two hundred eighty".