9782678721 has 16 divisors (see below), whose sum is σ = 13537339200. Its totient is φ = 6276368448.

The previous prime is 9782678707. The next prime is 9782678729. The reversal of 9782678721 is 1278762879.

9782678721 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 9782678721 - 2²⁵ = 9749124289 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9782678729) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 156426 + ... + 209843.

It is an arithmetic number, because the mean of its divisors is an integer number (846083700).

Almost surely, 2^9782678721 is an apocalyptic number.

It is an amenable number.

9782678721 is a deficient number, since it is larger than the sum of its proper divisors (3754660479).

9782678721 is a wasteful number, since it uses less digits than its factorization.

9782678721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 366608.

The product of its digits is 4741632, while the sum is 57.

The square root of 9782678721 is about 98907.4250043949. The cubic root of 9782678721 is about 2138.7134317680.

The spelling of 9782678721 in words is "nine billion, seven hundred eighty-two million, six hundred seventy-eight thousand, seven hundred twenty-one".