396809681 has 2 divisors, whose sum is σ = 396809682. Its totient is φ = 396809680.

The previous prime is 396809669. The next prime is 396809687. The reversal of 396809681 is 186908693.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 385140625 + 11669056 = 19625^2 + 3416^2 .

It is a cyclic number.

It is not a de Polignac number, because 396809681 - 2⁶ = 396809617 is a prime.

It is a super-2 number, since 2×396809681² = 314915845870643522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (396809687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 198404840 + 198404841.

It is an arithmetic number, because the mean of its divisors is an integer number (198404841).

Almost surely, 2^396809681 is an apocalyptic number.

It is an amenable number.

396809681 is a deficient number, since it is larger than the sum of its proper divisors (1).

396809681 is an equidigital number, since it uses as much as digits as its factorization.

396809681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 559872, while the sum is 50.

The square root of 396809681 is about 19920.0823542474. The cubic root of 396809681 is about 734.8421960571.

The spelling of 396809681 in words is "three hundred ninety-six million, eight hundred nine thousand, six hundred eighty-one".