9825721 has 4 divisors (see below), whose sum is σ = 9890944. Its totient is φ = 9760500.

The previous prime is 9825713. The next prime is 9825731. The reversal of 9825721 is 1275289.

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: 1275289 = 17 ⋅75017.

It is a cyclic number.

It is not a de Polignac number, because 9825721 - 2³ = 9825713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9825701) 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, 32385 + ... + 32686.

It is an arithmetic number, because the mean of its divisors is an integer number (2472736).

Almost surely, 2^9825721 is an apocalyptic number.

It is an amenable number.

9825721 is a deficient number, since it is larger than the sum of its proper divisors (65223).

9825721 is a wasteful number, since it uses less digits than its factorization.

9825721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65222.

The product of its digits is 10080, while the sum is 34.

The square root of 9825721 is about 3134.6006125183. The cubic root of 9825721 is about 214.1845512543.

The spelling of 9825721 in words is "nine million, eight hundred twenty-five thousand, seven hundred twenty-one".