19490221 has 2 divisors, whose sum is σ = 19490222. Its totient is φ = 19490220.

The previous prime is 19490209. The next prime is 19490239. The reversal of 19490221 is 12209491.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18748900 + 741321 = 4330^2 + 861^2 .

It is a cyclic number.

It is not a de Polignac number, because 19490221 - 2⁹ = 19489709 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19490221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19490201) 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, 9745110 + 9745111.

It is an arithmetic number, because the mean of its divisors is an integer number (9745111).

Almost surely, 2^19490221 is an apocalyptic number.

It is an amenable number.

19490221 is a deficient number, since it is larger than the sum of its proper divisors (1).

19490221 is an equidigital number, since it uses as much as digits as its factorization.

19490221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 19490221 is about 4414.7730405990. The cubic root of 19490221 is about 269.1156295459.

The spelling of 19490221 in words is "nineteen million, four hundred ninety thousand, two hundred twenty-one".