18461021 has 2 divisors, whose sum is σ = 18461022. Its totient is φ = 18461020.

The previous prime is 18461017. The next prime is 18461057. The reversal of 18461021 is 12016481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11464996 + 6996025 = 3386^2 + 2645^2 .

It is an emirp because it is prime and its reverse (12016481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18461021 - 2² = 18461017 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 (18461011) 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, 9230510 + 9230511.

It is an arithmetic number, because the mean of its divisors is an integer number (9230511).

Almost surely, 2^18461021 is an apocalyptic number.

It is an amenable number.

18461021 is a deficient number, since it is larger than the sum of its proper divisors (1).

18461021 is an equidigital number, since it uses as much as digits as its factorization.

18461021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 18461021 is about 4296.6290275052. The cubic root of 18461021 is about 264.2927432546.

The spelling of 18461021 in words is "eighteen million, four hundred sixty-one thousand, twenty-one".