321691 has 8 divisors (see below), whose sum is σ = 345600. Its totient is φ = 298368.

The previous prime is 321679. The next prime is 321707. The reversal of 321691 is 196123.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-321691 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 (321611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2085 + ... + 2233.

It is an arithmetic number, because the mean of its divisors is an integer number (43200).

2³²¹⁶⁹¹ is an apocalyptic number.

321691 is a deficient number, since it is larger than the sum of its proper divisors (23909).

321691 is a wasteful number, since it uses less digits than its factorization.

321691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293.

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

The square root of 321691 is about 567.1781025392. The cubic root of 321691 is about 68.5193083190.

The spelling of 321691 in words is "three hundred twenty-one thousand, six hundred ninety-one".