1659669561 has 16 divisors (see below), whose sum is σ = 2682294720. Its totient is φ = 1005860160.

The previous prime is 1659669559. The next prime is 1659669569.

1659669561 is a `hidden beast` number, since 16 + 5 + 9 + 6 + 69 + 561 = 666.

1659669561 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1659669561 - 2¹ = 1659669559 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1659669498 and 1659669507.

It is not an unprimeable number, because it can be changed into a prime (1659669569) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2793760 + ... + 2794353.

It is an arithmetic number, because the mean of its divisors is an integer number (167643420).

Almost surely, 2^1659669561 is an apocalyptic number.

1659669561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1659669561 is a deficient number, since it is larger than the sum of its proper divisors (1022625159).

1659669561 is a wasteful number, since it uses less digits than its factorization.

1659669561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5588133 (or 5588127 counting only the distinct ones).

The product of its digits is 2624400, while the sum is 54.

The square root of 1659669561 is about 40739.0422199639. The cubic root of 1659669561 is about 1183.9695769305.

The spelling of 1659669561 in words is "one billion, six hundred fifty-nine million, six hundred sixty-nine thousand, five hundred sixty-one".