9981551 has 2 divisors, whose sum is σ = 9981552. Its totient is φ = 9981550.

The previous prime is 9981467. The next prime is 9981557. The reversal of 9981551 is 1551899.

It is a strong prime.

It is an emirp because it is prime and its reverse (1551899) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9981551 - 2¹⁸ = 9719407 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 (9981557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4990775 + 4990776.

It is an arithmetic number, because the mean of its divisors is an integer number (4990776).

Almost surely, 2^9981551 is an apocalyptic number.

9981551 is a deficient number, since it is larger than the sum of its proper divisors (1).

9981551 is an equidigital number, since it uses as much as digits as its factorization.

9981551 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 9981551 is about 3159.3592704851. The cubic root of 9981551 is about 215.3108968903.

The spelling of 9981551 in words is "nine million, nine hundred eighty-one thousand, five hundred fifty-one".