1648805661 has 18 divisors (see below), whose sum is σ = 2422048538. Its totient is φ = 1080560160.

The previous prime is 1648805621. The next prime is 1648805749. The reversal of 1648805661 is 1665088461.

1648805661 is a `hidden beast` number, since 1 + 6 + 4 + 8 + 80 + 566 + 1 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 1988100 + 1646817561 = 1410^2 + 40581^2 .

It is not a de Polignac number, because 1648805661 - 2⁹ = 1648805149 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1648805621) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 950551 + ... + 952283.

Almost surely, 2^1648805661 is an apocalyptic number.

It is an amenable number.

1648805661 is a deficient number, since it is larger than the sum of its proper divisors (773242877).

1648805661 is an frugal number, since it uses more digits than its factorization.

1648805661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3533 (or 1797 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The square root of 1648805661 is about 40605.4880650387. The cubic root of 1648805661 is about 1181.3805686191.

The spelling of 1648805661 in words is "one billion, six hundred forty-eight million, eight hundred five thousand, six hundred sixty-one".