9721220 has 12 divisors (see below), whose sum is σ = 20414604. Its totient is φ = 3888480.

The previous prime is 9721199. The next prime is 9721241. The reversal of 9721220 is 221279.

It is an interprime number because it is at equal distance from previous prime (9721199) and next prime (9721241).

It can be written as a sum of positive squares in 2 ways, for example, as 2709316 + 7011904 = 1646^2 + 2648^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 243011 + ... + 243050.

It is an arithmetic number, because the mean of its divisors is an integer number (1701217).

Almost surely, 2^9721220 is an apocalyptic number.

It is an amenable number.

9721220 is an abundant number, since it is smaller than the sum of its proper divisors (10693384).

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

9721220 is a wasteful number, since it uses less digits than its factorization.

9721220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 486070 (or 486068 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 9721220 is about 3117.8871050761. The cubic root of 9721220 is about 213.4225267227.

Adding to 9721220 its reverse (221279), we get a palindrome (9942499).

The spelling of 9721220 in words is "nine million, seven hundred twenty-one thousand, two hundred twenty".