9687721 has 2 divisors, whose sum is σ = 9687722. Its totient is φ = 9687720.

The previous prime is 9687719. The next prime is 9687751. The reversal of 9687721 is 1277869.

9687721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8555625 + 1132096 = 2925^2 + 1064^2 .

It is a cyclic number.

It is not a de Polignac number, because 9687721 - 2¹ = 9687719 is a prime.

Together with 9687719, it forms a pair of twin primes.

It is a Chen prime.

9687721 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (9687751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4843860 + 4843861.

It is an arithmetic number, because the mean of its divisors is an integer number (4843861).

Almost surely, 2^9687721 is an apocalyptic number.

It is an amenable number.

9687721 is a deficient number, since it is larger than the sum of its proper divisors (1).

9687721 is an equidigital number, since it uses as much as digits as its factorization.

9687721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 42336, while the sum is 40.

The square root of 9687721 is about 3112.5104015890. The cubic root of 9687721 is about 213.1770956202.

The spelling of 9687721 in words is "nine million, six hundred eighty-seven thousand, seven hundred twenty-one".