18417227021 has 2 divisors, whose sum is σ = 18417227022. Its totient is φ = 18417227020.

The previous prime is 18417226969. The next prime is 18417227051. The reversal of 18417227021 is 12072271481.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18368380900 + 48846121 = 135530^2 + 6989^2 .

It is an emirp because it is prime and its reverse (12072271481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18417227021 - 2²² = 18413032717 is a prime.

It is a super-2 number, since 2×18417227021² (a number of 21 digits) contains 22 as substring.

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 (18417227051) 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, 9208613510 + 9208613511.

It is an arithmetic number, because the mean of its divisors is an integer number (9208613511).

Almost surely, 2^18417227021 is an apocalyptic number.

It is an amenable number.

18417227021 is a deficient number, since it is larger than the sum of its proper divisors (1).

18417227021 is an equidigital number, since it uses as much as digits as its factorization.

18417227021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12544, while the sum is 35.

The spelling of 18417227021 in words is "eighteen billion, four hundred seventeen million, two hundred twenty-seven thousand, twenty-one".