19328021 has 2 divisors, whose sum is σ = 19328022. Its totient is φ = 19328020.

The previous prime is 19328017. The next prime is 19328039. The reversal of 19328021 is 12082391.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18748900 + 579121 = 4330^2 + 761^2 .

It is an emirp because it is prime and its reverse (12082391) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19328021 - 2² = 19328017 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19328011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9664010 + 9664011.

It is an arithmetic number, because the mean of its divisors is an integer number (9664011).

Almost surely, 2^19328021 is an apocalyptic number.

It is an amenable number.

19328021 is a deficient number, since it is larger than the sum of its proper divisors (1).

19328021 is an equidigital number, since it uses as much as digits as its factorization.

19328021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 19328021 is about 4396.3645208285. The cubic root of 19328021 is about 268.3670112774.

The spelling of 19328021 in words is "nineteen million, three hundred twenty-eight thousand, twenty-one".