378821 has 2 divisors, whose sum is σ = 378822. Its totient is φ = 378820.

The previous prime is 378817. The next prime is 378823. The reversal of 378821 is 128873.

378821 is nontrivially palindromic in base 16.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 297025 + 81796 = 545^2 + 286^2 .

It is an emirp because it is prime and its reverse (128873) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 378821 - 2² = 378817 is a prime.

Together with 378823, 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 (378823) 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, 189410 + 189411.

It is an arithmetic number, because the mean of its divisors is an integer number (189411).

2³⁷⁸⁸²¹ is an apocalyptic number.

It is an amenable number.

378821 is a deficient number, since it is larger than the sum of its proper divisors (1).

378821 is an equidigital number, since it uses as much as digits as its factorization.

378821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 29.

The square root of 378821 is about 615.4843621084. The cubic root of 378821 is about 72.3565773420.

The spelling of 378821 in words is "three hundred seventy-eight thousand, eight hundred twenty-one".