1386821 has 2 divisors, whose sum is σ = 1386822. Its totient is φ = 1386820.

The previous prime is 1386811. The next prime is 1386823. The reversal of 1386821 is 1286831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1288225 + 98596 = 1135^2 + 314^2 .

It is a cyclic number.

It is not a de Polignac number, because 1386821 - 2⁶ = 1386757 is a prime.

Together with 1386823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1386823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 693410 + 693411.

It is an arithmetic number, because the mean of its divisors is an integer number (693411).

2^1386821 is an apocalyptic number.

It is an amenable number.

1386821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1386821 is an equidigital number, since it uses as much as digits as its factorization.

1386821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2304, while the sum is 29.

The square root of 1386821 is about 1177.6336442205. The cubic root of 1386821 is about 111.5167583249.

The spelling of 1386821 in words is "one million, three hundred eighty-six thousand, eight hundred twenty-one".