1280821 has 2 divisors, whose sum is σ = 1280822. Its totient is φ = 1280820.

The previous prime is 1280803. The next prime is 1280833.

1280821 is nontrivially palindromic in base 10.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1199025 + 81796 = 1095^2 + 286^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 1280821 - 2⁵ = 1280789 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1280792 and 1280801.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1280221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 640410 + 640411.

It is an arithmetic number, because the mean of its divisors is an integer number (640411).

2^1280821 is an apocalyptic number.

It is an amenable number.

1280821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1280821 is an equidigital number, since it uses as much as digits as its factorization.

1280821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 1280821 is about 1131.7336259032. The cubic root of 1280821 is about 108.5999136280.

The spelling of 1280821 in words is "one million, two hundred eighty thousand, eight hundred twenty-one".