491394161 has 2 divisors, whose sum is σ = 491394162. Its totient is φ = 491394160.

The previous prime is 491394139. The next prime is 491394179. The reversal of 491394161 is 161493194.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 313998400 + 177395761 = 17720^2 + 13319^2 .

It is a cyclic number.

It is not a de Polignac number, because 491394161 - 2²² = 487199857 is a prime.

It is equal to p_25926059 and since 491394161 and 25926059 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (491394181) 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, 245697080 + 245697081.

It is an arithmetic number, because the mean of its divisors is an integer number (245697081).

Almost surely, 2^491394161 is an apocalyptic number.

It is an amenable number.

491394161 is a deficient number, since it is larger than the sum of its proper divisors (1).

491394161 is an equidigital number, since it uses as much as digits as its factorization.

491394161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23328, while the sum is 38.

The square root of 491394161 is about 22167.4121403469. The cubic root of 491394161 is about 789.1205087185.

The spelling of 491394161 in words is "four hundred ninety-one million, three hundred ninety-four thousand, one hundred sixty-one".