9721660 has 48 divisors (see below), whose sum is σ = 22226400. Its totient is φ = 3550464.

The previous prime is 9721643. The next prime is 9721667. The reversal of 9721660 is 661279.

9721660 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9721667) 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, 36006 + ... + 36274.

It is an arithmetic number, because the mean of its divisors is an integer number (463050).

Almost surely, 2^9721660 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9721660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11113200).

9721660 is an abundant number, since it is smaller than the sum of its proper divisors (12504740).

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

9721660 is a wasteful number, since it uses less digits than its factorization.

9721660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 430 (or 428 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 9721660 is about 3117.9576648826. The cubic root of 9721660 is about 213.4257466373.

The spelling of 9721660 in words is "nine million, seven hundred twenty-one thousand, six hundred sixty".