400331221 has 4 divisors (see below), whose sum is σ = 400371244. Its totient is φ = 400291200.

The previous prime is 400331219. The next prime is 400331279. The reversal of 400331221 is 122133004.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 341732196 + 58599025 = 18486^2 + 7655^2 .

It is a cyclic number.

It is not a de Polignac number, because 400331221 - 2¹ = 400331219 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 400331195 and 400331204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400331201) 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, 9511 + ... + 29851.

It is an arithmetic number, because the mean of its divisors is an integer number (100092811).

Almost surely, 2^400331221 is an apocalyptic number.

It is an amenable number.

400331221 is a deficient number, since it is larger than the sum of its proper divisors (40023).

400331221 is a wasteful number, since it uses less digits than its factorization.

400331221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40022.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 400331221 is about 20008.2788115320. The cubic root of 400331221 is about 737.0096150526.

Adding to 400331221 its reverse (122133004), we get a palindrome (522464225).

The spelling of 400331221 in words is "four hundred million, three hundred thirty-one thousand, two hundred twenty-one".