9724221 has 24 divisors (see below), whose sum is σ = 16019640. Its totient is φ = 5630976.

The previous prime is 9724213. The next prime is 9724223. The reversal of 9724221 is 1224279.

It can be written as a sum of positive squares in 4 ways, for example, as 1822500 + 7901721 = 1350^2 + 2811^2 .

It is not a de Polignac number, because 9724221 - 2³ = 9724213 is a prime.

9724221 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9724223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 456 + ... + 4433.

It is an arithmetic number, because the mean of its divisors is an integer number (667485).

Almost surely, 2^9724221 is an apocalyptic number.

It is an amenable number.

9724221 is a deficient number, since it is larger than the sum of its proper divisors (6295419).

9724221 is a wasteful number, since it uses less digits than its factorization.

9724221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4925 (or 4922 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 9724221 is about 3118.3683233383. The cubic root of 9724221 is about 213.4444860758. Note that the first 4 decimals are identical.

The spelling of 9724221 in words is "nine million, seven hundred twenty-four thousand, two hundred twenty-one".