9789721 has 4 divisors (see below), whose sum is σ = 9811152. Its totient is φ = 9768292.

The previous prime is 9789713. The next prime is 9789727. The reversal of 9789721 is 1279879.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 9789721 - 2³ = 9789713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9789727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10015 + ... + 10948.

It is an arithmetic number, because the mean of its divisors is an integer number (2452788).

Almost surely, 2^9789721 is an apocalyptic number.

It is an amenable number.

9789721 is a deficient number, since it is larger than the sum of its proper divisors (21431).

9789721 is a wasteful number, since it uses less digits than its factorization.

9789721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21430.

The product of its digits is 63504, while the sum is 43.

The square root of 9789721 is about 3128.8529847214. The cubic root of 9789721 is about 213.9226508825.

The spelling of 9789721 in words is "nine million, seven hundred eighty-nine thousand, seven hundred twenty-one".