1656689 has 2 divisors, whose sum is σ = 1656690. Its totient is φ = 1656688.

The previous prime is 1656679. The next prime is 1656719. The reversal of 1656689 is 9866561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1227664 + 429025 = 1108^2 + 655^2 .

It is an emirp because it is prime and its reverse (9866561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1656689 - 2⁴ = 1656673 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1656649) 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 as a sum of consecutive naturals, namely, 828344 + 828345.

It is an arithmetic number, because the mean of its divisors is an integer number (828345).

2^1656689 is an apocalyptic number.

It is an amenable number.

1656689 is a deficient number, since it is larger than the sum of its proper divisors (1).

1656689 is an equidigital number, since it uses as much as digits as its factorization.

1656689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 41.

The square root of 1656689 is about 1287.1243141204. The cubic root of 1656689 is about 118.3260397982.

The spelling of 1656689 in words is "one million, six hundred fifty-six thousand, six hundred eighty-nine".