18685751321 has 2 divisors, whose sum is σ = 18685751322. Its totient is φ = 18685751320.

The previous prime is 18685751317. The next prime is 18685751327. The reversal of 18685751321 is 12315758681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14430015625 + 4255735696 = 120125^2 + 65236^2 .

It is a cyclic number.

It is not a de Polignac number, because 18685751321 - 2² = 18685751317 is a prime.

It is not a weakly prime, because it can be changed into another prime (18685751327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9342875660 + 9342875661.

It is an arithmetic number, because the mean of its divisors is an integer number (9342875661).

Almost surely, 2^18685751321 is an apocalyptic number.

It is an amenable number.

18685751321 is a deficient number, since it is larger than the sum of its proper divisors (1).

18685751321 is an equidigital number, since it uses as much as digits as its factorization.

18685751321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 403200, while the sum is 47.

The spelling of 18685751321 in words is "eighteen billion, six hundred eighty-five million, seven hundred fifty-one thousand, three hundred twenty-one".