1666685353 has 4 divisors (see below), whose sum is σ = 1668701520. Its totient is φ = 1664669188.

The previous prime is 1666685351. The next prime is 1666685399. The reversal of 1666685353 is 3535866661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3535866661 = 42697 ⋅82813.

It is a cyclic number.

It is not a de Polignac number, because 1666685353 - 2¹ = 1666685351 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1666685297 and 1666685306.

It is not an unprimeable number, because it can be changed into a prime (1666685351) 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 in 3 ways as a sum of consecutive naturals, for example, 1006843 + ... + 1008496.

It is an arithmetic number, because the mean of its divisors is an integer number (417175380).

Almost surely, 2^1666685353 is an apocalyptic number.

It is an amenable number.

1666685353 is a deficient number, since it is larger than the sum of its proper divisors (2016167).

1666685353 is an equidigital number, since it uses as much as digits as its factorization.

1666685353 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2016166.

The product of its digits is 2332800, while the sum is 49.

The square root of 1666685353 is about 40825.0579056540. The cubic root of 1666685353 is about 1185.6355324997.

The spelling of 1666685353 in words is "one billion, six hundred sixty-six million, six hundred eighty-five thousand, three hundred fifty-three".