8720191 has 2 divisors, whose sum is σ = 8720192. Its totient is φ = 8720190.

The previous prime is 8720189. The next prime is 8720227. The reversal of 8720191 is 1910278.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 8720191 - 2¹ = 8720189 is a prime.

Together with 8720189, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8720111) 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, 4360095 + 4360096.

It is an arithmetic number, because the mean of its divisors is an integer number (4360096).

Almost surely, 2^8720191 is an apocalyptic number.

8720191 is a deficient number, since it is larger than the sum of its proper divisors (1).

8720191 is an equidigital number, since it uses as much as digits as its factorization.

8720191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 8720191 is about 2952.9969522504. The cubic root of 8720191 is about 205.8299961031.

It can be divided in two parts, 8720 and 191, that added together give a triangular number (8911 = T₁₃₃).

The spelling of 8720191 in words is "eight million, seven hundred twenty thousand, one hundred ninety-one".