9840851984581 has 2 divisors, whose sum is σ = 9840851984582. Its totient is φ = 9840851984580.

The previous prime is 9840851984507. The next prime is 9840851984597. The reversal of 9840851984581 is 1854891580489.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8502297856900 + 1338554127681 = 2915870^2 + 1156959^2 .

It is an emirp because it is prime and its reverse (1854891580489) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9840851984581 - 2³⁹ = 9291096170693 is a prime.

It is a super-2 number, since 2×9840851984581² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 9840851984581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9840851984501) 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, 4920425992290 + 4920425992291.

It is an arithmetic number, because the mean of its divisors is an integer number (4920425992291).

Almost surely, 2^{9840851984581} is an apocalyptic number.

It is an amenable number.

9840851984581 is a deficient number, since it is larger than the sum of its proper divisors (1).

9840851984581 is an equidigital number, since it uses as much as digits as its factorization.

9840851984581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 132710400, while the sum is 70.

The spelling of 9840851984581 in words is "nine trillion, eight hundred forty billion, eight hundred fifty-one million, nine hundred eighty-four thousand, five hundred eighty-one".