6656685389 has 2 divisors, whose sum is σ = 6656685390. Its totient is φ = 6656685388.

The previous prime is 6656685379. The next prime is 6656685437. The reversal of 6656685389 is 9835866566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5523016489 + 1133668900 = 74317^2 + 33670^2 .

It is a cyclic number.

It is not a de Polignac number, because 6656685389 - 2²⁴ = 6639908173 is a prime.

It is a super-2 number, since 2×6656685389² = 88622920736252162642, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6656685319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3328342694 + 3328342695.

It is an arithmetic number, because the mean of its divisors is an integer number (3328342695).

Almost surely, 2^6656685389 is an apocalyptic number.

It is an amenable number.

6656685389 is a deficient number, since it is larger than the sum of its proper divisors (1).

6656685389 is an equidigital number, since it uses as much as digits as its factorization.

6656685389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 55987200, while the sum is 62.

The square root of 6656685389 is about 81588.5126044102. The cubic root of 6656685389 is about 1881.1323144241.

The spelling of 6656685389 in words is "six billion, six hundred fifty-six million, six hundred eighty-five thousand, three hundred eighty-nine".