27218021 has 2 divisors, whose sum is σ = 27218022. Its totient is φ = 27218020.

The previous prime is 27217987. The next prime is 27218027. The reversal of 27218021 is 12081272.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21390625 + 5827396 = 4625^2 + 2414^2 .

It is a cyclic number.

It is not a de Polignac number, because 27218021 - 2¹⁰ = 27216997 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27218027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13609010 + 13609011.

It is an arithmetic number, because the mean of its divisors is an integer number (13609011).

Almost surely, 2^27218021 is an apocalyptic number.

It is an amenable number.

27218021 is a deficient number, since it is larger than the sum of its proper divisors (1).

27218021 is an equidigital number, since it uses as much as digits as its factorization.

27218021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 27218021 is about 5217.0893226013. The cubic root of 27218021 is about 300.8053214420.

Adding to 27218021 its reverse (12081272), we get a palindrome (39299293).

The spelling of 27218021 in words is "twenty-seven million, two hundred eighteen thousand, twenty-one".