6401221 has 6 divisors (see below), whose sum is σ = 6615366. Its totient is φ = 6193800.

The previous prime is 6401203. The next prime is 6401249. The reversal of 6401221 is 1221046.

It can be written as a sum of positive squares in only one way, i.e., 6305121 + 96100 = 2511^2 + 310^2 .

It is not a de Polignac number, because 6401221 - 2⁷ = 6401093 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 6401195 and 6401204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6401621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2370 + ... + 4291.

It is an arithmetic number, because the mean of its divisors is an integer number (1102561).

Almost surely, 2^6401221 is an apocalyptic number.

It is an amenable number.

6401221 is a deficient number, since it is larger than the sum of its proper divisors (214145).

6401221 is an equidigital number, since it uses as much as digits as its factorization.

6401221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6723 (or 6692 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 6401221 is about 2530.0634379398. The cubic root of 6401221 is about 185.6753596353.

Adding to 6401221 its reverse (1221046), we get a palindrome (7622267).

The spelling of 6401221 in words is "six million, four hundred one thousand, two hundred twenty-one".