396378821 has 2 divisors, whose sum is σ = 396378822. Its totient is φ = 396378820.

The previous prime is 396378809. The next prime is 396378841. The reversal of 396378821 is 128873693.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 384552100 + 11826721 = 19610^2 + 3439^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-396378821 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (396378841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 198189410 + 198189411.

It is an arithmetic number, because the mean of its divisors is an integer number (198189411).

Almost surely, 2^396378821 is an apocalyptic number.

It is an amenable number.

396378821 is a deficient number, since it is larger than the sum of its proper divisors (1).

396378821 is an equidigital number, since it uses as much as digits as its factorization.

396378821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 435456, while the sum is 47.

The square root of 396378821 is about 19909.2647026453. The cubic root of 396378821 is about 734.5761333515.

The spelling of 396378821 in words is "three hundred ninety-six million, three hundred seventy-eight thousand, eight hundred twenty-one".