400031221 has 2 divisors, whose sum is σ = 400031222. Its totient is φ = 400031220.

The previous prime is 400031213. The next prime is 400031231. The reversal of 400031221 is 122130004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 278723025 + 121308196 = 16695^2 + 11014^2 .

It is a cyclic number.

It is not a de Polignac number, because 400031221 - 2³ = 400031213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400031231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200015610 + 200015611.

It is an arithmetic number, because the mean of its divisors is an integer number (200015611).

Almost surely, 2^400031221 is an apocalyptic number.

It is an amenable number.

400031221 is a deficient number, since it is larger than the sum of its proper divisors (1).

400031221 is an equidigital number, since it uses as much as digits as its factorization.

400031221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 400031221 is about 20000.7805097701. The cubic root of 400031221 is about 736.8254690873.

Adding to 400031221 its reverse (122130004), we get a palindrome (522161225).

The spelling of 400031221 in words is "four hundred million, thirty-one thousand, two hundred twenty-one".