18021371 has 2 divisors, whose sum is σ = 18021372. Its totient is φ = 18021370.

The previous prime is 18021347. The next prime is 18021379. The reversal of 18021371 is 17312081.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (17312081) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18021371 - 2⁶ = 18021307 is a prime.

It is not a weakly prime, because it can be changed into another prime (18021379) 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 as a sum of consecutive naturals, namely, 9010685 + 9010686.

It is an arithmetic number, because the mean of its divisors is an integer number (9010686).

Almost surely, 2^18021371 is an apocalyptic number.

18021371 is a deficient number, since it is larger than the sum of its proper divisors (1).

18021371 is an equidigital number, since it uses as much as digits as its factorization.

18021371 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 23.

The square root of 18021371 is about 4245.1585364978. The cubic root of 18021371 is about 262.1778166678.

The spelling of 18021371 in words is "eighteen million, twenty-one thousand, three hundred seventy-one".