16820861 has 2 divisors, whose sum is σ = 16820862. Its totient is φ = 16820860.

The previous prime is 16820857. The next prime is 16820891. The reversal of 16820861 is 16802861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16760836 + 60025 = 4094^2 + 245^2 .

It is a cyclic number.

It is not a de Polignac number, because 16820861 - 2² = 16820857 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 (16820801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8410430 + 8410431.

It is an arithmetic number, because the mean of its divisors is an integer number (8410431).

Almost surely, 2^16820861 is an apocalyptic number.

It is an amenable number.

16820861 is a deficient number, since it is larger than the sum of its proper divisors (1).

16820861 is an equidigital number, since it uses as much as digits as its factorization.

16820861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 16820861 is about 4101.3242983212. The cubic root of 16820861 is about 256.2217977291.

The spelling of 16820861 in words is "sixteen million, eight hundred twenty thousand, eight hundred sixty-one".