16609518661 has 8 divisors (see below), whose sum is σ = 16673874840. Its totient is φ = 16545215232.

The previous prime is 16609518659. The next prime is 16609518671. The reversal of 16609518661 is 16681590661.

It can be written as a sum of positive squares in 4 ways, for example, as 18533025 + 16590985636 = 4305^2 + 128806^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 16609518661 - 2¹ = 16609518659 is a prime.

It is a super-2 number, since 2×16609518661² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16609518671) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 689305 + ... + 712993.

It is an arithmetic number, because the mean of its divisors is an integer number (2084234355).

Almost surely, 2^16609518661 is an apocalyptic number.

It is an amenable number.

16609518661 is a deficient number, since it is larger than the sum of its proper divisors (64356179).

16609518661 is a wasteful number, since it uses less digits than its factorization.

16609518661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26375.

The product of its (nonzero) digits is 466560, while the sum is 49.

The spelling of 16609518661 in words is "sixteen billion, six hundred nine million, five hundred eighteen thousand, six hundred sixty-one".