9712721 has 4 divisors (see below), whose sum is σ = 9753600. Its totient is φ = 9671844.

The previous prime is 9712699. The next prime is 9712751. The reversal of 9712721 is 1272179.

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: 1272179 = 859 ⋅1481.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9712721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9712751) 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, 20081 + ... + 20558.

It is an arithmetic number, because the mean of its divisors is an integer number (2438400).

Almost surely, 2^9712721 is an apocalyptic number.

It is an amenable number.

9712721 is a deficient number, since it is larger than the sum of its proper divisors (40879).

9712721 is a wasteful number, since it uses less digits than its factorization.

9712721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40878.

The product of its digits is 1764, while the sum is 29.

The square root of 9712721 is about 3116.5238648212. The cubic root of 9712721 is about 213.3603120720.

The spelling of 9712721 in words is "nine million, seven hundred twelve thousand, seven hundred twenty-one".