9721009591 has 2 divisors, whose sum is σ = 9721009592. Its totient is φ = 9721009590.

The previous prime is 9721009589. The next prime is 9721009601. The reversal of 9721009591 is 1959001279.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9721009591 - 2¹ = 9721009589 is a prime.

Together with 9721009589, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9721009511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4860504795 + 4860504796.

It is an arithmetic number, because the mean of its divisors is an integer number (4860504796).

Almost surely, 2^9721009591 is an apocalyptic number.

9721009591 is a deficient number, since it is larger than the sum of its proper divisors (1).

9721009591 is an equidigital number, since it uses as much as digits as its factorization.

9721009591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51030, while the sum is 43.

The square root of 9721009591 is about 98595.1803639509. The cubic root of 9721009591 is about 2134.2098691785.

The spelling of 9721009591 in words is "nine billion, seven hundred twenty-one million, nine thousand, five hundred ninety-one".