491215091 has 2 divisors, whose sum is σ = 491215092. Its totient is φ = 491215090.

The previous prime is 491215063. The next prime is 491215093. The reversal of 491215091 is 190512194.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 491215091 - 2¹⁰ = 491214067 is a prime.

It is a super-2 number, since 2×491215091² = 482584531252276562, which contains 22 as substring.

Together with 491215093, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (491215093) 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, 245607545 + 245607546.

It is an arithmetic number, because the mean of its divisors is an integer number (245607546).

Almost surely, 2^491215091 is an apocalyptic number.

491215091 is a deficient number, since it is larger than the sum of its proper divisors (1).

491215091 is an equidigital number, since it uses as much as digits as its factorization.

491215091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 32.

The square root of 491215091 is about 22163.3727352134. The cubic root of 491215091 is about 789.0246420403.

The spelling of 491215091 in words is "four hundred ninety-one million, two hundred fifteen thousand, ninety-one".