9888097721 has 2 divisors, whose sum is σ = 9888097722. Its totient is φ = 9888097720.

The previous prime is 9888097663. The next prime is 9888097729. The reversal of 9888097721 is 1277908889.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6014778025 + 3873319696 = 77555^2 + 62236^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9888097721 is a prime.

It is not a weakly prime, because it can be changed into another prime (9888097729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4944048860 + 4944048861.

It is an arithmetic number, because the mean of its divisors is an integer number (4944048861).

Almost surely, 2^9888097721 is an apocalyptic number.

It is an amenable number.

9888097721 is a deficient number, since it is larger than the sum of its proper divisors (1).

9888097721 is an equidigital number, since it uses as much as digits as its factorization.

9888097721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4064256, while the sum is 59.

The square root of 9888097721 is about 99438.9145204230. The cubic root of 9888097721 is about 2146.3683215633.

The spelling of 9888097721 in words is "nine billion, eight hundred eighty-eight million, ninety-seven thousand, seven hundred twenty-one".