16558285561 has 4 divisors (see below), whose sum is σ = 16558611300. Its totient is φ = 16557959824.

The previous prime is 16558285553. The next prime is 16558285573.

16558285561 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13281410025 + 3276875536 = 115245^2 + 57244^2 .

It is a cyclic number.

It is not a de Polignac number, because 16558285561 - 2³ = 16558285553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16558285499 and 16558285508.

It is not an unprimeable number, because it can be changed into a prime (16558285531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68326 + ... + 194383.

It is an arithmetic number, because the mean of its divisors is an integer number (4139652825).

Almost surely, 2^16558285561 is an apocalyptic number.

It is an amenable number.

16558285561 is a deficient number, since it is larger than the sum of its proper divisors (325739).

16558285561 is an equidigital number, since it uses as much as digits as its factorization.

16558285561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325738.

The product of its digits is 2880000, while the sum is 52.

The spelling of 16558285561 in words is "sixteen billion, five hundred fifty-eight million, two hundred eighty-five thousand, five hundred sixty-one".