404666221 has 4 divisors (see below), whose sum is σ = 408247452. Its totient is φ = 401084992.

The previous prime is 404666201. The next prime is 404666231. The reversal of 404666221 is 122666404.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 115326121 + 289340100 = 10739^2 + 17010^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-404666221 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (404666201) 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 in 3 ways as a sum of consecutive naturals, for example, 1790446 + ... + 1790671.

It is an arithmetic number, because the mean of its divisors is an integer number (102061863).

Almost surely, 2^404666221 is an apocalyptic number.

It is an amenable number.

404666221 is a deficient number, since it is larger than the sum of its proper divisors (3581231).

404666221 is a wasteful number, since it uses less digits than its factorization.

404666221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3581230.

The product of its (nonzero) digits is 13824, while the sum is 31.

The square root of 404666221 is about 20116.3172822463. The cubic root of 404666221 is about 739.6603146347.

The spelling of 404666221 in words is "four hundred four million, six hundred sixty-six thousand, two hundred twenty-one".