1667221 has 8 divisors (see below), whose sum is σ = 1723680. Its totient is φ = 1611792.

The previous prime is 1667213. The next prime is 1667227. The reversal of 1667221 is 1227661.

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

It is a cyclic number.

It is not a de Polignac number, because 1667221 - 2³ = 1667213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1667227) 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, 4210 + ... + 4588.

It is an arithmetic number, because the mean of its divisors is an integer number (215460).

2^1667221 is an apocalyptic number.

It is an amenable number.

1667221 is a deficient number, since it is larger than the sum of its proper divisors (56459).

1667221 is an equidigital number, since it uses as much as digits as its factorization.

1667221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515.

The product of its digits is 1008, while the sum is 25.

The square root of 1667221 is about 1291.2091232639. The cubic root of 1667221 is about 118.5762533894.

The spelling of 1667221 in words is "one million, six hundred sixty-seven thousand, two hundred twenty-one".