400022221 has 2 divisors, whose sum is σ = 400022222. Its totient is φ = 400022220.

The previous prime is 400022213. The next prime is 400022243. The reversal of 400022221 is 122220004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 230736100 + 169286121 = 15190^2 + 13011^2 .

It is a cyclic number.

It is not a de Polignac number, because 400022221 - 2³ = 400022213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400022521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200011110 + 200011111.

It is an arithmetic number, because the mean of its divisors is an integer number (200011111).

Almost surely, 2^400022221 is an apocalyptic number.

It is an amenable number.

400022221 is a deficient number, since it is larger than the sum of its proper divisors (1).

400022221 is an equidigital number, since it uses as much as digits as its factorization.

400022221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 13.

The square root of 400022221 is about 20000.5555172850. Note that the first 4 decimals coincide. The cubic root of 400022221 is about 736.8199432861.

Adding to 400022221 its reverse (122220004), we get a palindrome (522242225).

The spelling of 400022221 in words is "four hundred million, twenty-two thousand, two hundred twenty-one".