18938471 has 2 divisors, whose sum is σ = 18938472. Its totient is φ = 18938470.

The previous prime is 18938443. The next prime is 18938477. The reversal of 18938471 is 17483981.

It is a strong prime.

It is an emirp because it is prime and its reverse (17483981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18938471 - 2¹⁸ = 18676327 is a prime.

It is a super-3 number, since 3×18938471³ (a number of 23 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18938477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9469235 + 9469236.

It is an arithmetic number, because the mean of its divisors is an integer number (9469236).

Almost surely, 2^18938471 is an apocalyptic number.

18938471 is a deficient number, since it is larger than the sum of its proper divisors (1).

18938471 is an equidigital number, since it uses as much as digits as its factorization.

18938471 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48384, while the sum is 41.

The square root of 18938471 is about 4351.8353599372. The cubic root of 18938471 is about 266.5518111281.

The spelling of 18938471 in words is "eighteen million, nine hundred thirty-eight thousand, four hundred seventy-one".