918631321 has 2 divisors, whose sum is σ = 918631322. Its totient is φ = 918631320.

The previous prime is 918631319. The next prime is 918631327. The reversal of 918631321 is 123136819.

918631321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 613255696 + 305375625 = 24764^2 + 17475^2 .

It is a cyclic number.

It is not a de Polignac number, because 918631321 - 2¹ = 918631319 is a prime.

Together with 918631319, it forms a pair of twin primes.

It is equal to p_46913047 and since 918631321 and 46913047 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (918631327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 459315660 + 459315661.

It is an arithmetic number, because the mean of its divisors is an integer number (459315661).

Almost surely, 2^918631321 is an apocalyptic number.

It is an amenable number.

918631321 is a deficient number, since it is larger than the sum of its proper divisors (1).

918631321 is an equidigital number, since it uses as much as digits as its factorization.

918631321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 34.

The square root of 918631321 is about 30308.9313734417. The cubic root of 918631321 is about 972.1062818098.

The spelling of 918631321 in words is "nine hundred eighteen million, six hundred thirty-one thousand, three hundred twenty-one".