321680991 has 8 divisors (see below), whose sum is σ = 430182064. Its totient is φ = 213816960.

The previous prime is 321680981. The next prime is 321681011. The reversal of 321680991 is 199086123.

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

It is not a de Polignac number, because 321680991 - 2⁵ = 321680959 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 (321680941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 158080 + ... + 160101.

It is an arithmetic number, because the mean of its divisors is an integer number (53772758).

Almost surely, 2^321680991 is an apocalyptic number.

321680991 is a deficient number, since it is larger than the sum of its proper divisors (108501073).

321680991 is a wasteful number, since it uses less digits than its factorization.

321680991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318521.

The product of its (nonzero) digits is 23328, while the sum is 39.

The square root of 321680991 is about 17935.4674040015. The cubic root of 321680991 is about 685.1859768175.

The spelling of 321680991 in words is "three hundred twenty-one million, six hundred eighty thousand, nine hundred ninety-one".