691123 has 4 divisors (see below), whose sum is σ = 709840. Its totient is φ = 672408.

The previous prime is 691121. The next prime is 691129. The reversal of 691123 is 321196.

691123 is nontrivially palindromic in base 15.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 691123 - 2¹ = 691121 is a prime.

It is a super-2 number, since 2×691123² = 955302002258, which contains 22 as substring.

It is a Duffinian number.

691123 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 691094 and 691103.

It is not an unprimeable number, because it can be changed into a prime (691121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9303 + ... + 9376.

It is an arithmetic number, because the mean of its divisors is an integer number (177460).

2⁶⁹¹¹²³ is an apocalyptic number.

691123 is a deficient number, since it is larger than the sum of its proper divisors (18717).

691123 is a wasteful number, since it uses less digits than its factorization.

691123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18716.

The product of its digits is 324, while the sum is 22.

The square root of 691123 is about 831.3380780405. The cubic root of 691123 is about 88.4134726229.

The spelling of 691123 in words is "six hundred ninety-one thousand, one hundred twenty-three".