19704221 has 2 divisors, whose sum is σ = 19704222. Its totient is φ = 19704220.

The previous prime is 19704211. The next prime is 19704247. The reversal of 19704221 is 12240791.

It is an a-pointer prime, because the next prime (19704247) can be obtained adding 19704221 to its sum of digits (26).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16240900 + 3463321 = 4030^2 + 1861^2 .

It is a cyclic number.

It is not a de Polignac number, because 19704221 - 2²² = 15509917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19704211) 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, 9852110 + 9852111.

It is an arithmetic number, because the mean of its divisors is an integer number (9852111).

Almost surely, 2^19704221 is an apocalyptic number.

It is an amenable number.

19704221 is a deficient number, since it is larger than the sum of its proper divisors (1).

19704221 is an equidigital number, since it uses as much as digits as its factorization.

19704221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 19704221 is about 4438.9436806520. The cubic root of 19704221 is about 270.0969976140.

The spelling of 19704221 in words is "nineteen million, seven hundred four thousand, two hundred twenty-one".