404878217 has 2 divisors, whose sum is σ = 404878218. Its totient is φ = 404878216.

The previous prime is 404878181. The next prime is 404878219. The reversal of 404878217 is 712878404.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 396647056 + 8231161 = 19916^2 + 2869^2 .

It is a cyclic number.

It is not a de Polignac number, because 404878217 - 2²⁶ = 337769353 is a prime.

Together with 404878219, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (404878219) 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, 202439108 + 202439109.

It is an arithmetic number, because the mean of its divisors is an integer number (202439109).

Almost surely, 2^404878217 is an apocalyptic number.

It is an amenable number.

404878217 is a deficient number, since it is larger than the sum of its proper divisors (1).

404878217 is an equidigital number, since it uses as much as digits as its factorization.

404878217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100352, while the sum is 41.

The square root of 404878217 is about 20121.5858470450. The cubic root of 404878217 is about 739.7894561722.

The spelling of 404878217 in words is "four hundred four million, eight hundred seventy-eight thousand, two hundred seventeen".