820911281 has 2 divisors, whose sum is σ = 820911282. Its totient is φ = 820911280.

The previous prime is 820911233. The next prime is 820911361. The reversal of 820911281 is 182119028.

820911281 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 791578225 + 29333056 = 28135^2 + 5416^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820911281 is a prime.

It is a super-2 number, since 2×820911281² = 1347790662546121922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (820911211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410455640 + 410455641.

It is an arithmetic number, because the mean of its divisors is an integer number (410455641).

Almost surely, 2^820911281 is an apocalyptic number.

It is an amenable number.

820911281 is a deficient number, since it is larger than the sum of its proper divisors (1).

820911281 is an equidigital number, since it uses as much as digits as its factorization.

820911281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 32.

The square root of 820911281 is about 28651.5493647377. The cubic root of 820911281 is about 936.3367616148.

The spelling of 820911281 in words is "eight hundred twenty million, nine hundred eleven thousand, two hundred eighty-one".