818784671321 has 2 divisors, whose sum is σ = 818784671322. Its totient is φ = 818784671320.

The previous prime is 818784671267. The next prime is 818784671333. The reversal of 818784671321 is 123176487818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 694203909721 + 124580761600 = 833189^2 + 352960^2 .

It is a cyclic number.

It is not a de Polignac number, because 818784671321 - 2¹⁴ = 818784654937 is a prime.

It is not a weakly prime, because it can be changed into another prime (818784671381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 409392335660 + 409392335661.

It is an arithmetic number, because the mean of its divisors is an integer number (409392335661).

Almost surely, 2^818784671321 is an apocalyptic number.

It is an amenable number.

818784671321 is a deficient number, since it is larger than the sum of its proper divisors (1).

818784671321 is an equidigital number, since it uses as much as digits as its factorization.

818784671321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3612672, while the sum is 56.

The spelling of 818784671321 in words is "eight hundred eighteen billion, seven hundred eighty-four million, six hundred seventy-one thousand, three hundred twenty-one".