18211120321 has 2 divisors, whose sum is σ = 18211120322. Its totient is φ = 18211120320.

The previous prime is 18211120313. The next prime is 18211120331. The reversal of 18211120321 is 12302111281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9454839696 + 8756280625 = 97236^2 + 93575^2 .

It is an emirp because it is prime and its reverse (12302111281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18211120321 - 2³ = 18211120313 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18211120292 and 18211120301.

It is not a weakly prime, because it can be changed into another prime (18211120331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9105560160 + 9105560161.

It is an arithmetic number, because the mean of its divisors is an integer number (9105560161).

Almost surely, 2^18211120321 is an apocalyptic number.

It is an amenable number.

18211120321 is a deficient number, since it is larger than the sum of its proper divisors (1).

18211120321 is an equidigital number, since it uses as much as digits as its factorization.

18211120321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 22.

The spelling of 18211120321 in words is "eighteen billion, two hundred eleven million, one hundred twenty thousand, three hundred twenty-one".