396662821 has 2 divisors, whose sum is σ = 396662822. Its totient is φ = 396662820.

The previous prime is 396662789. The next prime is 396662837. The reversal of 396662821 is 128266693.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 295358596 + 101304225 = 17186^2 + 10065^2 .

It is an emirp because it is prime and its reverse (128266693) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 396662821 - 2⁵ = 396662789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (396660821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 198331410 + 198331411.

It is an arithmetic number, because the mean of its divisors is an integer number (198331411).

Almost surely, 2^396662821 is an apocalyptic number.

It is an amenable number.

396662821 is a deficient number, since it is larger than the sum of its proper divisors (1).

396662821 is an equidigital number, since it uses as much as digits as its factorization.

396662821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 186624, while the sum is 43.

The square root of 396662821 is about 19916.3957833741. The cubic root of 396662821 is about 734.7515293836.

The spelling of 396662821 in words is "three hundred ninety-six million, six hundred sixty-two thousand, eight hundred twenty-one".