9810721 has 4 divisors (see below), whose sum is σ = 9885744. Its totient is φ = 9735700.

The previous prime is 9810653. The next prime is 9810781. The reversal of 9810721 is 1270189.

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: 1270189 = 17 ⋅74717.

It is a cyclic number.

It is not a de Polignac number, because 9810721 - 2⁹ = 9810209 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 9810721.

It is not an unprimeable number, because it can be changed into a prime (9810781) 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 3 ways as a sum of consecutive naturals, for example, 37315 + ... + 37576.

It is an arithmetic number, because the mean of its divisors is an integer number (2471436).

Almost surely, 2^9810721 is an apocalyptic number.

It is an amenable number.

9810721 is a deficient number, since it is larger than the sum of its proper divisors (75023).

9810721 is a wasteful number, since it uses less digits than its factorization.

9810721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75022.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 9810721 is about 3132.2070493503. The cubic root of 9810721 is about 214.0755039714.

The spelling of 9810721 in words is "nine million, eight hundred ten thousand, seven hundred twenty-one".