17930021 has 2 divisors, whose sum is σ = 17930022. Its totient is φ = 17930020.

The previous prime is 17929999. The next prime is 17930039. The reversal of 17930021 is 12003971.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17757796 + 172225 = 4214^2 + 415^2 .

It is a cyclic number.

It is not a de Polignac number, because 17930021 - 2⁶ = 17929957 is a prime.

It is a Sophie Germain prime.

It is a Chen 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 (17930051) 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, 8965010 + 8965011.

It is an arithmetic number, because the mean of its divisors is an integer number (8965011).

Almost surely, 2^17930021 is an apocalyptic number.

It is an amenable number.

17930021 is a deficient number, since it is larger than the sum of its proper divisors (1).

17930021 is an equidigital number, since it uses as much as digits as its factorization.

17930021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 378, while the sum is 23.

The square root of 17930021 is about 4234.3855516474. The cubic root of 17930021 is about 261.7340745282.

Adding to 17930021 its reverse (12003971), we get a palindrome (29933992).

The spelling of 17930021 in words is "seventeen million, nine hundred thirty thousand, twenty-one".