400221818 has 8 divisors (see below), whose sum is σ = 605645748. Its totient is φ = 198339904.

The previous prime is 400221751. The next prime is 400221889. The reversal of 400221818 is 818122004.

It can be written as a sum of positive squares in 2 ways, for example, as 313042249 + 87179569 = 17693^2 + 9337^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 885221 + ... + 885672.

Almost surely, 2^400221818 is an apocalyptic number.

400221818 is a deficient number, since it is larger than the sum of its proper divisors (205423930).

400221818 is a wasteful number, since it uses less digits than its factorization.

400221818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1771008.

The product of its (nonzero) digits is 1024, while the sum is 26.

The square root of 400221818 is about 20005.5446814127. The cubic root of 400221818 is about 736.9424719765.

The spelling of 400221818 in words is "four hundred million, two hundred twenty-one thousand, eight hundred eighteen".