9876721 has 4 divisors (see below), whose sum is σ = 10086912. Its totient is φ = 9666532.

The previous prime is 9876719. The next prime is 9876761. The reversal of 9876721 is 1276789.

9876721 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1276789 = 83 ⋅15383.

It is a cyclic number.

It is not a de Polignac number, because 9876721 - 2¹ = 9876719 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9876701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105025 + ... + 105118.

It is an arithmetic number, because the mean of its divisors is an integer number (2521728).

Almost surely, 2^9876721 is an apocalyptic number.

It is an amenable number.

9876721 is a deficient number, since it is larger than the sum of its proper divisors (210191).

9876721 is a wasteful number, since it uses less digits than its factorization.

9876721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210190.

The product of its digits is 42336, while the sum is 40.

The square root of 9876721 is about 3142.7250913817. The cubic root of 9876721 is about 214.5544839799.

The spelling of 9876721 in words is "nine million, eight hundred seventy-six thousand, seven hundred twenty-one".