321687397 has 4 divisors (see below), whose sum is σ = 322404300. Its totient is φ = 320970496.

The previous prime is 321687319. The next prime is 321687409. The reversal of 321687397 is 793786123.

It is a happy number.

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 164711556 + 156975841 = 12834^2 + 12529^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-321687397 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 (321681397) 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, 357778 + ... + 358675.

It is an arithmetic number, because the mean of its divisors is an integer number (80601075).

Almost surely, 2^321687397 is an apocalyptic number.

It is an amenable number.

321687397 is a deficient number, since it is larger than the sum of its proper divisors (716903).

321687397 is an equidigital number, since it uses as much as digits as its factorization.

321687397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 716902.

The product of its digits is 381024, while the sum is 46.

The square root of 321687397 is about 17935.6459878087. The cubic root of 321687397 is about 685.1905250835.

The spelling of 321687397 in words is "three hundred twenty-one million, six hundred eighty-seven thousand, three hundred ninety-seven".