9851356561 has 2 divisors, whose sum is σ = 9851356562. Its totient is φ = 9851356560.

The previous prime is 9851356477. The next prime is 9851356583. The reversal of 9851356561 is 1656531589.

9851356561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6780534336 + 3070822225 = 82344^2 + 55415^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9851356561 is a prime.

It is not a weakly prime, because it can be changed into another prime (9851356661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4925678280 + 4925678281.

It is an arithmetic number, because the mean of its divisors is an integer number (4925678281).

Almost surely, 2^9851356561 is an apocalyptic number.

It is an amenable number.

9851356561 is a deficient number, since it is larger than the sum of its proper divisors (1).

9851356561 is an equidigital number, since it uses as much as digits as its factorization.

9851356561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 972000, while the sum is 49.

The square root of 9851356561 is about 99254.0002266911. Note that the first 3 decimals coincide. The cubic root of 9851356561 is about 2143.7066051038.

The spelling of 9851356561 in words is "nine billion, eight hundred fifty-one million, three hundred fifty-six thousand, five hundred sixty-one".