9820191 has 4 divisors (see below), whose sum is σ = 13093592. Its totient is φ = 6546792.

The previous prime is 9820189. The next prime is 9820199. The reversal of 9820191 is 1910289.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1910289 = 3 ⋅636763.

It is not a de Polignac number, because 9820191 - 2¹ = 9820189 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9820199) 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 in 3 ways as a sum of consecutive naturals, for example, 1636696 + ... + 1636701.

It is an arithmetic number, because the mean of its divisors is an integer number (3273398).

Almost surely, 2^9820191 is an apocalyptic number.

9820191 is a deficient number, since it is larger than the sum of its proper divisors (3273401).

9820191 is a wasteful number, since it uses less digits than its factorization.

9820191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3273400.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 9820191 is about 3133.7183983249. The cubic root of 9820191 is about 214.1443620800.

It can be divided in two parts, 9820 and 191, that added together give a triangular number (10011 = T₁₄₁).

The spelling of 9820191 in words is "nine million, eight hundred twenty thousand, one hundred ninety-one".