821213361 has 6 divisors (see below), whose sum is σ = 1186197090. Its totient is φ = 547475568.

The previous prime is 821213311. The next prime is 821213363. The reversal of 821213361 is 163312128.

It is a happy number.

821213361 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 461390400 + 359822961 = 21480^2 + 18969^2 .

It is not a de Polignac number, because 821213361 - 2⁶ = 821213297 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821213363) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 45622956 + ... + 45622973.

It is an arithmetic number, because the mean of its divisors is an integer number (197699515).

Almost surely, 2^821213361 is an apocalyptic number.

It is an amenable number.

821213361 is a deficient number, since it is larger than the sum of its proper divisors (364983729).

821213361 is a wasteful number, since it uses less digits than its factorization.

821213361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91245935 (or 91245932 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 821213361 is about 28656.8204970475. The cubic root of 821213361 is about 936.4515990027.

Adding to 821213361 its reverse (163312128), we get a palindrome (984525489).

The spelling of 821213361 in words is "eight hundred twenty-one million, two hundred thirteen thousand, three hundred sixty-one".