821081 has 2 divisors, whose sum is σ = 821082. Its totient is φ = 821080.

The previous prime is 821069. The next prime is 821089. The reversal of 821081 is 180128.

821081 is digitally balanced in base 2, because in such base 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., 648025 + 173056 = 805^2 + 416^2 .

It is a cyclic number.

It is not a de Polignac number, because 821081 - 2¹⁴ = 804697 is a prime.

It is a super-2 number, since 2×821081² = 1348348017122, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (821089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410540 + 410541.

It is an arithmetic number, because the mean of its divisors is an integer number (410541).

2⁸²¹⁰⁸¹ is an apocalyptic number.

It is an amenable number.

821081 is a deficient number, since it is larger than the sum of its proper divisors (1).

821081 is an equidigital number, since it uses as much as digits as its factorization.

821081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 20.

The square root of 821081 is about 906.1351996253. The cubic root of 821081 is about 93.6401284701.

The spelling of 821081 in words is "eight hundred twenty-one thousand, eighty-one".