1668555505 has 4 divisors (see below), whose sum is σ = 2002266612. Its totient is φ = 1334844400.

The previous prime is 1668555467. The next prime is 1668555521. The reversal of 1668555505 is 5055558661.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5055558661 = 29 ⋅174329609.

It can be written as a sum of positive squares in 2 ways, for example, as 320123664 + 1348431841 = 17892^2 + 36721^2 .

It is not a de Polignac number, because 1668555505 - 2¹³ = 1668547313 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166855546 + ... + 166855555.

It is an arithmetic number, because the mean of its divisors is an integer number (500566653).

Almost surely, 2^1668555505 is an apocalyptic number.

It is an amenable number.

1668555505 is a deficient number, since it is larger than the sum of its proper divisors (333711107).

1668555505 is an equidigital number, since it uses as much as digits as its factorization.

1668555505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333711106.

The product of its (nonzero) digits is 900000, while the sum is 46.

The square root of 1668555505 is about 40847.9559464118. The cubic root of 1668555505 is about 1186.0788254983.

The spelling of 1668555505 in words is "one billion, six hundred sixty-eight million, five hundred fifty-five thousand, five hundred five".