9516756721 has 2 divisors, whose sum is σ = 9516756722. Its totient is φ = 9516756720.

The previous prime is 9516756719. The next prime is 9516756737. The reversal of 9516756721 is 1276576159.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9165381696 + 351375025 = 95736^2 + 18745^2 .

It is a cyclic number.

It is not a de Polignac number, because 9516756721 - 2¹ = 9516756719 is a prime.

Together with 9516756719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (9516756121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4758378360 + 4758378361.

It is an arithmetic number, because the mean of its divisors is an integer number (4758378361).

Almost surely, 2^9516756721 is an apocalyptic number.

It is an amenable number.

9516756721 is a deficient number, since it is larger than the sum of its proper divisors (1).

9516756721 is an equidigital number, since it uses as much as digits as its factorization.

9516756721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 793800, while the sum is 49.

The square root of 9516756721 is about 97553.8657409331. The cubic root of 9516756721 is about 2119.1562977884.

The spelling of 9516756721 in words is "nine billion, five hundred sixteen million, seven hundred fifty-six thousand, seven hundred twenty-one".