6401222221 has 2 divisors, whose sum is σ = 6401222222. Its totient is φ = 6401222220.

The previous prime is 6401222213. The next prime is 6401222231. The reversal of 6401222221 is 1222221046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4596162025 + 1805060196 = 67795^2 + 42486^2 .

It is a cyclic number.

It is not a de Polignac number, because 6401222221 - 2³ = 6401222213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 6401222192 and 6401222201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6401222231) by changing a digit.

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 as a sum of consecutive naturals, namely, 3200611110 + 3200611111.

It is an arithmetic number, because the mean of its divisors is an integer number (3200611111).

Almost surely, 2^6401222221 is an apocalyptic number.

It is an amenable number.

6401222221 is a deficient number, since it is larger than the sum of its proper divisors (1).

6401222221 is an equidigital number, since it uses as much as digits as its factorization.

6401222221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 6401222221 is about 80007.6385165817. The cubic root of 6401222221 is about 1856.7537144087.

Adding to 6401222221 its reverse (1222221046), we get a palindrome (7623443267).

The spelling of 6401222221 in words is "six billion, four hundred one million, two hundred twenty-two thousand, two hundred twenty-one".