1664207 has 4 divisors (see below), whose sum is σ = 1666896. Its totient is φ = 1661520.

The previous prime is 1664123. The next prime is 1664227. The reversal of 1664207 is 7024661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1664207 - 2⁸ = 1663951 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 (1664227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107 + ... + 1827.

It is an arithmetic number, because the mean of its divisors is an integer number (416724).

2^1664207 is an apocalyptic number.

1664207 is a deficient number, since it is larger than the sum of its proper divisors (2689).

1664207 is an equidigital number, since it uses as much as digits as its factorization.

1664207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2688.

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 1664207 is about 1290.0414722016. The cubic root of 1664207 is about 118.5047562881.

Adding to 1664207 its reverse (7024661), we get a palindrome (8688868).

The spelling of 1664207 in words is "one million, six hundred sixty-four thousand, two hundred seven".