9822821821 has 2 divisors, whose sum is σ = 9822821822. Its totient is φ = 9822821820.

The previous prime is 9822821803. The next prime is 9822821881. The reversal of 9822821821 is 1281282289.

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., 9668788900 + 154032921 = 98330^2 + 12411^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9822821821 is a prime.

It is a super-2 number, since 2×9822821821² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9822821881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4911410910 + 4911410911.

It is an arithmetic number, because the mean of its divisors is an integer number (4911410911).

Almost surely, 2^9822821821 is an apocalyptic number.

It is an amenable number.

9822821821 is a deficient number, since it is larger than the sum of its proper divisors (1).

9822821821 is an equidigital number, since it uses as much as digits as its factorization.

9822821821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 73728, while the sum is 43.

The square root of 9822821821 is about 99110.1499393478. The cubic root of 9822821821 is about 2141.6348340474.

The spelling of 9822821821 in words is "nine billion, eight hundred twenty-two million, eight hundred twenty-one thousand, eight hundred twenty-one".