1664779 has 4 divisors (see below), whose sum is σ = 1674576. Its totient is φ = 1654984.

The previous prime is 1664771. The next prime is 1664797. The reversal of 1664779 is 9774661.

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 1664779 - 2³ = 1664771 is a prime.

It is a Duffinian number.

1664779 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1664771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4639 + ... + 4984.

It is an arithmetic number, because the mean of its divisors is an integer number (418644).

2^1664779 is an apocalyptic number.

1664779 is a deficient number, since it is larger than the sum of its proper divisors (9797).

1664779 is an equidigital number, since it uses as much as digits as its factorization.

1664779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9796.

The product of its digits is 63504, while the sum is 40.

The square root of 1664779 is about 1290.2631514540. The cubic root of 1664779 is about 118.5183317139.

The spelling of 1664779 in words is "one million, six hundred sixty-four thousand, seven hundred seventy-nine".