19794221 has 2 divisors, whose sum is σ = 19794222. Its totient is φ = 19794220.

The previous prime is 19794209. The next prime is 19794241. The reversal of 19794221 is 12249791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15015625 + 4778596 = 3875^2 + 2186^2 .

It is an emirp because it is prime and its reverse (12249791) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19794221 - 2¹⁰ = 19793197 is a prime.

It is a super-2 number, since 2×19794221² = 783622369993682, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19794241) 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, 9897110 + 9897111.

It is an arithmetic number, because the mean of its divisors is an integer number (9897111).

Almost surely, 2^19794221 is an apocalyptic number.

It is an amenable number.

19794221 is a deficient number, since it is larger than the sum of its proper divisors (1).

19794221 is an equidigital number, since it uses as much as digits as its factorization.

19794221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 35.

The square root of 19794221 is about 4449.0696780338. The cubic root of 19794221 is about 270.5076002115.

The spelling of 19794221 in words is "nineteen million, seven hundred ninety-four thousand, two hundred twenty-one".