691673 has 4 divisors (see below), whose sum is σ = 697908. Its totient is φ = 685440.

The previous prime is 691661. The next prime is 691681. The reversal of 691673 is 376196.

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

It can be written as a sum of positive squares in 2 ways, for example, as 38809 + 652864 = 197^2 + 808^2 .

It is a cyclic number.

It is not a de Polignac number, because 691673 - 2¹⁸ = 429529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691693) 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, 2948 + ... + 3173.

It is an arithmetic number, because the mean of its divisors is an integer number (174477).

2⁶⁹¹⁶⁷³ is an apocalyptic number.

It is an amenable number.

691673 is a deficient number, since it is larger than the sum of its proper divisors (6235).

691673 is a wasteful number, since it uses less digits than its factorization.

691673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6234.

The product of its digits is 6804, while the sum is 32.

The square root of 691673 is about 831.6688042725. The cubic root of 691673 is about 88.4369197355.

The spelling of 691673 in words is "six hundred ninety-one thousand, six hundred seventy-three".