6667221 has 12 divisors (see below), whose sum is σ = 9771776. Its totient is φ = 4040520.

The previous prime is 6667207. The next prime is 6667223. The reversal of 6667221 is 1227666.

It is not a de Polignac number, because 6667221 - 2¹⁴ = 6650837 is a prime.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6667223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8821 + ... + 9546.

Almost surely, 2^6667221 is an apocalyptic number.

It is an amenable number.

6667221 is a deficient number, since it is larger than the sum of its proper divisors (3104555).

6667221 is a wasteful number, since it uses less digits than its factorization.

6667221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18392 (or 18381 counting only the distinct ones).

The product of its digits is 6048, while the sum is 30.

The square root of 6667221 is about 2582.0962414287. The cubic root of 6667221 is about 188.2124221080.

It can be divided in two parts, 666 and 7221, that added together give a palindrome (7887).

The spelling of 6667221 in words is "six million, six hundred sixty-seven thousand, two hundred twenty-one".