667221 has 8 divisors (see below), whose sum is σ = 913824. Its totient is φ = 432720.

The previous prime is 667211. The next prime is 667229. The reversal of 667221 is 122766.

It is a happy number.

667221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 667221 - 2¹⁷ = 536149 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 667191 and 667200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2895 + ... + 3116.

It is an arithmetic number, because the mean of its divisors is an integer number (114228).

2⁶⁶⁷²²¹ is an apocalyptic number.

It is an amenable number.

667221 is a deficient number, since it is larger than the sum of its proper divisors (246603).

667221 is a wasteful number, since it uses less digits than its factorization.

667221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6051.

The product of its digits is 1008, while the sum is 24.

The square root of 667221 is about 816.8359688456. The cubic root of 667221 is about 87.3822525043.

Adding to 667221 its reverse (122766), we get a palindrome (789987).

It can be divided in two parts, 667 and 221, that added together give a palindrome (888).

The spelling of 667221 in words is "six hundred sixty-seven thousand, two hundred twenty-one".