18385021 has 2 divisors, whose sum is σ = 18385022. Its totient is φ = 18385020.

The previous prime is 18384991. The next prime is 18385033. The reversal of 18385021 is 12058381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11148921 + 7236100 = 3339^2 + 2690^2 .

It is an emirp because it is prime and its reverse (12058381) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18385021 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 (18385091) 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, 9192510 + 9192511.

It is an arithmetic number, because the mean of its divisors is an integer number (9192511).

Almost surely, 2^18385021 is an apocalyptic number.

It is an amenable number.

18385021 is a deficient number, since it is larger than the sum of its proper divisors (1).

18385021 is an equidigital number, since it uses as much as digits as its factorization.

18385021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 18385021 is about 4287.7757637265. The cubic root of 18385021 is about 263.9295658826.

It can be divided in two parts, 1838 and 5021, that added together give a cube (6859 = 19³).

The spelling of 18385021 in words is "eighteen million, three hundred eighty-five thousand, twenty-one".