1667321 has 2 divisors, whose sum is σ = 1667322. Its totient is φ = 1667320.

The previous prime is 1667311. The next prime is 1667329. The reversal of 1667321 is 1237661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1452025 + 215296 = 1205^2 + 464^2 .

It is an emirp because it is prime and its reverse (1237661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1667321 - 2¹⁰ = 1666297 is a prime.

It is not a weakly prime, because it can be changed into another prime (1667329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833660 + 833661.

It is an arithmetic number, because the mean of its divisors is an integer number (833661).

2^1667321 is an apocalyptic number.

It is an amenable number.

1667321 is a deficient number, since it is larger than the sum of its proper divisors (1).

1667321 is an equidigital number, since it uses as much as digits as its factorization.

1667321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1512, while the sum is 26.

The square root of 1667321 is about 1291.2478460776. The cubic root of 1667321 is about 118.5786240786.

The spelling of 1667321 in words is "one million, six hundred sixty-seven thousand, three hundred twenty-one".