8161591 has 2 divisors, whose sum is σ = 8161592. Its totient is φ = 8161590.

The previous prime is 8161589. The next prime is 8161607. The reversal of 8161591 is 1951618.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 8161591 - 2¹ = 8161589 is a prime.

It is a super-2 number, since 2×8161591² = 133223135302562, which contains 22 as substring.

Together with 8161589, it forms a pair of twin primes.

8161591 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8161511) 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, 4080795 + 4080796.

It is an arithmetic number, because the mean of its divisors is an integer number (4080796).

Almost surely, 2^8161591 is an apocalyptic number.

8161591 is a deficient number, since it is larger than the sum of its proper divisors (1).

8161591 is an equidigital number, since it uses as much as digits as its factorization.

8161591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 31.

The square root of 8161591 is about 2856.8498385459. The cubic root of 8161591 is about 201.3376255121.

The spelling of 8161591 in words is "eight million, one hundred sixty-one thousand, five hundred ninety-one".