9891551 has 2 divisors, whose sum is σ = 9891552. Its totient is φ = 9891550.

The previous prime is 9891517. The next prime is 9891589. The reversal of 9891551 is 1551989.

It is an a-pointer prime, because the next prime (9891589) can be obtained adding 9891551 to its sum of digits (38).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9891551 - 2⁶ = 9891487 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9891151) 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, 4945775 + 4945776.

It is an arithmetic number, because the mean of its divisors is an integer number (4945776).

Almost surely, 2^9891551 is an apocalyptic number.

9891551 is a deficient number, since it is larger than the sum of its proper divisors (1).

9891551 is an equidigital number, since it uses as much as digits as its factorization.

9891551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16200, while the sum is 38.

The square root of 9891551 is about 3145.0836236895. The cubic root of 9891551 is about 214.6618155461.

The spelling of 9891551 in words is "nine million, eight hundred ninety-one thousand, five hundred fifty-one".