18041921 has 2 divisors, whose sum is σ = 18041922. Its totient is φ = 18041920.

The previous prime is 18041911. The next prime is 18041939. The reversal of 18041921 is 12914081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13359025 + 4682896 = 3655^2 + 2164^2 .

It is an emirp because it is prime and its reverse (12914081) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18041921 - 2¹⁸ = 17779777 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18041911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9020960 + 9020961.

It is an arithmetic number, because the mean of its divisors is an integer number (9020961).

Almost surely, 2^18041921 is an apocalyptic number.

It is an amenable number.

18041921 is a deficient number, since it is larger than the sum of its proper divisors (1).

18041921 is an equidigital number, since it uses as much as digits as its factorization.

18041921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 26.

The square root of 18041921 is about 4247.5782511921. The cubic root of 18041921 is about 262.2774337191.

The spelling of 18041921 in words is "eighteen million, forty-one thousand, nine hundred twenty-one".