19368821 has 2 divisors, whose sum is σ = 19368822. Its totient is φ = 19368820.

The previous prime is 19368793. The next prime is 19368823. The reversal of 19368821 is 12886391.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19272100 + 96721 = 4390^2 + 311^2 .

It is a cyclic number.

It is not a de Polignac number, because 19368821 - 2¹⁰ = 19367797 is a prime.

Together with 19368823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19368823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9684410 + 9684411.

It is an arithmetic number, because the mean of its divisors is an integer number (9684411).

Almost surely, 2^19368821 is an apocalyptic number.

It is an amenable number.

19368821 is a deficient number, since it is larger than the sum of its proper divisors (1).

19368821 is an equidigital number, since it uses as much as digits as its factorization.

19368821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20736, while the sum is 38.

The square root of 19368821 is about 4401.0022722103. The cubic root of 19368821 is about 268.5557127598. Note that the first 3 decimals are identical.

The spelling of 19368821 in words is "nineteen million, three hundred sixty-eight thousand, eight hundred twenty-one".