18383921 has 2 divisors, whose sum is σ = 18383922. Its totient is φ = 18383920.

The previous prime is 18383903. The next prime is 18383927. The reversal of 18383921 is 12938381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12503296 + 5880625 = 3536^2 + 2425^2 .

It is a cyclic number.

It is not a de Polignac number, because 18383921 - 2¹⁴ = 18367537 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18383927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9191960 + 9191961.

It is an arithmetic number, because the mean of its divisors is an integer number (9191961).

Almost surely, 2^18383921 is an apocalyptic number.

It is an amenable number.

18383921 is a deficient number, since it is larger than the sum of its proper divisors (1).

18383921 is an equidigital number, since it uses as much as digits as its factorization.

18383921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 35.

The square root of 18383921 is about 4287.6474901745. The cubic root of 18383921 is about 263.9243020266.

The spelling of 18383921 in words is "eighteen million, three hundred eighty-three thousand, nine hundred twenty-one".