1664867 has 2 divisors, whose sum is σ = 1664868. Its totient is φ = 1664866.

The previous prime is 1664863. The next prime is 1664869. The reversal of 1664867 is 7684661.

It is a strong prime.

It is an emirp because it is prime and its reverse (7684661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1664867 - 2² = 1664863 is a prime.

Together with 1664869, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1664867.

It is not a weakly prime, because it can be changed into another prime (1664863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832433 + 832434.

It is an arithmetic number, because the mean of its divisors is an integer number (832434).

2^1664867 is an apocalyptic number.

1664867 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664867 is an equidigital number, since it uses as much as digits as its factorization.

1664867 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 38.

The square root of 1664867 is about 1290.2972525740. The cubic root of 1664867 is about 118.5204199649.

The spelling of 1664867 in words is "one million, six hundred sixty-four thousand, eight hundred sixty-seven".