691723 has 2 divisors, whose sum is σ = 691724. Its totient is φ = 691722.

The previous prime is 691721. The next prime is 691727. The reversal of 691723 is 327196.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 691723 - 2¹ = 691721 is a prime.

It is a super-3 number, since 3×691723³ = 992928333852450201, which contains 333 as substring.

Together with 691721, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 691691 and 691700.

It is not a weakly prime, because it can be changed into another prime (691721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345861 + 345862.

It is an arithmetic number, because the mean of its divisors is an integer number (345862).

2⁶⁹¹⁷²³ is an apocalyptic number.

691723 is a deficient number, since it is larger than the sum of its proper divisors (1).

691723 is an equidigital number, since it uses as much as digits as its factorization.

691723 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2268, while the sum is 28.

The square root of 691723 is about 831.6988637722. The cubic root of 691723 is about 88.4390506747.

The spelling of 691723 in words is "six hundred ninety-one thousand, seven hundred twenty-three".