400245221 has 2 divisors, whose sum is σ = 400245222. Its totient is φ = 400245220.

The previous prime is 400245187. The next prime is 400245233. The reversal of 400245221 is 122542004.

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., 393030625 + 7214596 = 19825^2 + 2686^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-400245221 is a prime.

It is a super-3 number, since 3×400245221³ (a number of 27 digits) contains 333 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 400245193 and 400245202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400295221) 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 as a sum of consecutive naturals, namely, 200122610 + 200122611.

It is an arithmetic number, because the mean of its divisors is an integer number (200122611).

Almost surely, 2^400245221 is an apocalyptic number.

It is an amenable number.

400245221 is a deficient number, since it is larger than the sum of its proper divisors (1).

400245221 is an equidigital number, since it uses as much as digits as its factorization.

400245221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 400245221 is about 20006.1295857045. The cubic root of 400245221 is about 736.9568359514.

Adding to 400245221 its reverse (122542004), we get a palindrome (522787225).

The spelling of 400245221 in words is "four hundred million, two hundred forty-five thousand, two hundred twenty-one".