19922821 has 2 divisors, whose sum is σ = 19922822. Its totient is φ = 19922820.

The previous prime is 19922779. The next prime is 19922839. The reversal of 19922821 is 12822991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19448100 + 474721 = 4410^2 + 689^2 .

It is a cyclic number.

It is not a de Polignac number, because 19922821 - 2²³ = 11534213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19922891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9961410 + 9961411.

It is an arithmetic number, because the mean of its divisors is an integer number (9961411).

Almost surely, 2^19922821 is an apocalyptic number.

It is an amenable number.

19922821 is a deficient number, since it is larger than the sum of its proper divisors (1).

19922821 is an equidigital number, since it uses as much as digits as its factorization.

19922821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 34.

The square root of 19922821 is about 4463.4987397780. The cubic root of 19922821 is about 271.0921515017.

The spelling of 19922821 in words is "nineteen million, nine hundred twenty-two thousand, eight hundred twenty-one".