18027521 has 2 divisors, whose sum is σ = 18027522. Its totient is φ = 18027520.

The previous prime is 18027511. The next prime is 18027533. The reversal of 18027521 is 12572081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17098225 + 929296 = 4135^2 + 964^2 .

It is a cyclic number.

It is not a de Polignac number, because 18027521 - 2¹⁴ = 18011137 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (18027511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9013760 + 9013761.

It is an arithmetic number, because the mean of its divisors is an integer number (9013761).

Almost surely, 2^18027521 is an apocalyptic number.

It is an amenable number.

18027521 is a deficient number, since it is larger than the sum of its proper divisors (1).

18027521 is an equidigital number, since it uses as much as digits as its factorization.

18027521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 18027521 is about 4245.8828292830. The cubic root of 18027521 is about 262.2076370070.

The spelling of 18027521 in words is "eighteen million, twenty-seven thousand, five hundred twenty-one".