16842821 has 2 divisors, whose sum is σ = 16842822. Its totient is φ = 16842820.

The previous prime is 16842809. The next prime is 16842851. The reversal of 16842821 is 12824861.

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., 13653025 + 3189796 = 3695^2 + 1786^2 .

It is a cyclic number.

It is not a de Polignac number, because 16842821 - 2⁶ = 16842757 is a prime.

It is a super-3 number, since 3×16842821³ (a number of 23 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16842851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8421410 + 8421411.

It is an arithmetic number, because the mean of its divisors is an integer number (8421411).

Almost surely, 2^16842821 is an apocalyptic number.

It is an amenable number.

16842821 is a deficient number, since it is larger than the sum of its proper divisors (1).

16842821 is an equidigital number, since it uses as much as digits as its factorization.

16842821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6144, while the sum is 32.

The square root of 16842821 is about 4104.0006091617. Note that the first 3 decimals coincide. The cubic root of 16842821 is about 256.3332502857. Note that the first 3 decimals are identical.

The spelling of 16842821 in words is "sixteen million, eight hundred forty-two thousand, eight hundred twenty-one".