9891813541 has 2 divisors, whose sum is σ = 9891813542. Its totient is φ = 9891813540.

The previous prime is 9891813509. The next prime is 9891813559. The reversal of 9891813541 is 1453181989.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8884005025 + 1007808516 = 94255^2 + 31746^2 .

It is a cyclic number.

It is not a de Polignac number, because 9891813541 - 2⁵ = 9891813509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9891813571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4945906770 + 4945906771.

It is an arithmetic number, because the mean of its divisors is an integer number (4945906771).

Almost surely, 2^9891813541 is an apocalyptic number.

It is an amenable number.

9891813541 is a deficient number, since it is larger than the sum of its proper divisors (1).

9891813541 is an equidigital number, since it uses as much as digits as its factorization.

9891813541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 311040, while the sum is 49.

The square root of 9891813541 is about 99457.5966982915. The cubic root of 9891813541 is about 2146.6371470994.

The spelling of 9891813541 in words is "nine billion, eight hundred ninety-one million, eight hundred thirteen thousand, five hundred forty-one".