691131169 has 2 divisors, whose sum is σ = 691131170. Its totient is φ = 691131168.

The previous prime is 691131167. The next prime is 691131173. The reversal of 691131169 is 961131196.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 644550544 + 46580625 = 25388^2 + 6825^2 .

It is a cyclic number.

It is not a de Polignac number, because 691131169 - 2¹ = 691131167 is a prime.

It is a super-2 number, since 2×691131169² = 955324585526613122, which contains 22 as substring.

Together with 691131167, 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 (691131167) 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, 345565584 + 345565585.

It is an arithmetic number, because the mean of its divisors is an integer number (345565585).

Almost surely, 2^691131169 is an apocalyptic number.

It is an amenable number.

691131169 is a deficient number, since it is larger than the sum of its proper divisors (1).

691131169 is an equidigital number, since it uses as much as digits as its factorization.

691131169 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8748, while the sum is 37.

The square root of 691131169 is about 26289.3736897629. The cubic root of 691131169 is about 884.1382096749.

The spelling of 691131169 in words is "six hundred ninety-one million, one hundred thirty-one thousand, one hundred sixty-nine".