9780120861 has 16 divisors (see below), whose sum is σ = 14904488064. Its totient is φ = 5588097984.

The previous prime is 9780120829. The next prime is 9780120869. The reversal of 9780120861 is 1680210879.

9780120861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 9780120861 - 2⁵ = 9780120829 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9780120869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 318751 + ... + 348083.

It is an arithmetic number, because the mean of its divisors is an integer number (931530504).

Almost surely, 2^9780120861 is an apocalyptic number.

It is an amenable number.

9780120861 is a deficient number, since it is larger than the sum of its proper divisors (5124367203).

9780120861 is a wasteful number, since it uses less digits than its factorization.

9780120861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45220.

The product of its (nonzero) digits is 48384, while the sum is 42.

The square root of 9780120861 is about 98894.4935828077. The cubic root of 9780120861 is about 2138.5270136252.

The spelling of 9780120861 in words is "nine billion, seven hundred eighty million, one hundred twenty thousand, eight hundred sixty-one".