691223 has 4 divisors (see below), whose sum is σ = 744408. Its totient is φ = 638040.

The previous prime is 691199. The next prime is 691231. The reversal of 691223 is 322196.

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

It is a de Polignac number, because none of the positive numbers 2^k-691223 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26573 + ... + 26598.

It is an arithmetic number, because the mean of its divisors is an integer number (186102).

2⁶⁹¹²²³ is an apocalyptic number.

691223 is a deficient number, since it is larger than the sum of its proper divisors (53185).

691223 is a wasteful number, since it uses less digits than its factorization.

691223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53184.

The product of its digits is 648, while the sum is 23.

The square root of 691223 is about 831.3982198682. The cubic root of 691223 is about 88.4177366593.

The spelling of 691223 in words is "six hundred ninety-one thousand, two hundred twenty-three".