1286821 has 2 divisors, whose sum is σ = 1286822. Its totient is φ = 1286820.

The previous prime is 1286819. The next prime is 1286833.

1286821 is nontrivially palindromic in base 10.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1050625 + 236196 = 1025^2 + 486^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 1286821 - 2¹ = 1286819 is a prime.

Together with 1286819, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1286821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1286881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 643410 + 643411.

It is an arithmetic number, because the mean of its divisors is an integer number (643411).

2^1286821 is an apocalyptic number.

It is an amenable number.

1286821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1286821 is an equidigital number, since it uses as much as digits as its factorization.

1286821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1536, while the sum is 28.

The square root of 1286821 is about 1134.3813291834. The cubic root of 1286821 is about 108.7692281146.

The spelling of 1286821 in words is "one million, two hundred eighty-six thousand, eight hundred twenty-one".