18193421 has 2 divisors, whose sum is σ = 18193422. Its totient is φ = 18193420.

The previous prime is 18193379. The next prime is 18193453. The reversal of 18193421 is 12439181.

18193421 is nontrivially palindromic in base 5.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11485321 + 6708100 = 3389^2 + 2590^2 .

It is a cyclic number.

It is not a de Polignac number, because 18193421 - 2¹⁴ = 18177037 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18193471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9096710 + 9096711.

It is an arithmetic number, because the mean of its divisors is an integer number (9096711).

Almost surely, 2^18193421 is an apocalyptic number.

It is an amenable number.

18193421 is a deficient number, since it is larger than the sum of its proper divisors (1).

18193421 is an equidigital number, since it uses as much as digits as its factorization.

18193421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1728, while the sum is 29.

The square root of 18193421 is about 4265.3746611523. The cubic root of 18193421 is about 263.0095125880.

The spelling of 18193421 in words is "eighteen million, one hundred ninety-three thousand, four hundred twenty-one".