16800821 has 2 divisors, whose sum is σ = 16800822. Its totient is φ = 16800820.

The previous prime is 16800799. The next prime is 16800827. The reversal of 16800821 is 12800861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14364100 + 2436721 = 3790^2 + 1561^2 .

It is a cyclic number.

It is not a de Polignac number, because 16800821 - 2⁶ = 16800757 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16800827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8400410 + 8400411.

It is an arithmetic number, because the mean of its divisors is an integer number (8400411).

Almost surely, 2^16800821 is an apocalyptic number.

It is an amenable number.

16800821 is a deficient number, since it is larger than the sum of its proper divisors (1).

16800821 is an equidigital number, since it uses as much as digits as its factorization.

16800821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 16800821 is about 4098.8804569053. The cubic root of 16800821 is about 256.1200049752.

The spelling of 16800821 in words is "sixteen million, eight hundred thousand, eight hundred twenty-one".