921000191 has 2 divisors, whose sum is σ = 921000192. Its totient is φ = 921000190.

The previous prime is 921000169. The next prime is 921000221. The reversal of 921000191 is 191000129.

It is a weak prime.

It is an emirp because it is prime and its reverse (191000129) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 921000191 - 2²⁶ = 853891327 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is equal to p_47028200 and since 921000191 and 47028200 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (921000161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460500095 + 460500096.

It is an arithmetic number, because the mean of its divisors is an integer number (460500096).

Almost surely, 2^921000191 is an apocalyptic number.

921000191 is a deficient number, since it is larger than the sum of its proper divisors (1).

921000191 is an equidigital number, since it uses as much as digits as its factorization.

921000191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162, while the sum is 23.

The square root of 921000191 is about 30347.9849578189. The cubic root of 921000191 is about 972.9411531325.

The spelling of 921000191 in words is "nine hundred twenty-one million, one hundred ninety-one", and thus it is an aban number.