9800821 has 2 divisors, whose sum is σ = 9800822. Its totient is φ = 9800820.

The previous prime is 9800803. The next prime is 9800831. The reversal of 9800821 is 1280089.

9800821 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9678321 + 122500 = 3111^2 + 350^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9800821 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 9800821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9800801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4900410 + 4900411.

It is an arithmetic number, because the mean of its divisors is an integer number (4900411).

Almost surely, 2^9800821 is an apocalyptic number.

It is an amenable number.

9800821 is a deficient number, since it is larger than the sum of its proper divisors (1).

9800821 is an equidigital number, since it uses as much as digits as its factorization.

9800821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 9800821 is about 3130.6262951684. The cubic root of 9800821 is about 214.0034718626.

The spelling of 9800821 in words is "nine million, eight hundred thousand, eight hundred twenty-one".