3678821 has 2 divisors, whose sum is σ = 3678822. Its totient is φ = 3678820.

The previous prime is 3678811. The next prime is 3678823. The reversal of 3678821 is 1288763.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3204100 + 474721 = 1790^2 + 689^2 .

It is a cyclic number.

It is not a de Polignac number, because 3678821 - 2¹⁴ = 3662437 is a prime.

It is a Sophie Germain prime.

Together with 3678823, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3678823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1839410 + 1839411.

It is an arithmetic number, because the mean of its divisors is an integer number (1839411).

Almost surely, 2^3678821 is an apocalyptic number.

It is an amenable number.

3678821 is a deficient number, since it is larger than the sum of its proper divisors (1).

3678821 is an equidigital number, since it uses as much as digits as its factorization.

3678821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128, while the sum is 35.

The square root of 3678821 is about 1918.0252865904. The cubic root of 3678821 is about 154.3723631036.

The spelling of 3678821 in words is "three million, six hundred seventy-eight thousand, eight hundred twenty-one".