821321377 has 2 divisors, whose sum is σ = 821321378. Its totient is φ = 821321376.

The previous prime is 821321353. The next prime is 821321419. The reversal of 821321377 is 773123128.

It is a happy number.

821321377 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., 652087296 + 169234081 = 25536^2 + 13009^2 .

It is a cyclic number.

It is not a de Polignac number, because 821321377 - 2¹¹ = 821319329 is a prime.

It is a super-3 number, since 3×821321377³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (821321777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410660688 + 410660689.

It is an arithmetic number, because the mean of its divisors is an integer number (410660689).

Almost surely, 2^821321377 is an apocalyptic number.

It is an amenable number.

821321377 is a deficient number, since it is larger than the sum of its proper divisors (1).

821321377 is an equidigital number, since it uses as much as digits as its factorization.

821321377 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14112, while the sum is 34.

The square root of 821321377 is about 28658.7050824004. The cubic root of 821321377 is about 936.4926550491.

The spelling of 821321377 in words is "eight hundred twenty-one million, three hundred twenty-one thousand, three hundred seventy-seven".