16005661 has 4 divisors (see below), whose sum is σ = 18292192. Its totient is φ = 13719132.

The previous prime is 16005623. The next prime is 16005673. The reversal of 16005661 is 16650061.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 16005661 - 2¹³ = 15997469 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16005611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1143255 + ... + 1143268.

It is an arithmetic number, because the mean of its divisors is an integer number (4573048).

Almost surely, 2^16005661 is an apocalyptic number.

It is an amenable number.

16005661 is a deficient number, since it is larger than the sum of its proper divisors (2286531).

16005661 is an equidigital number, since it uses as much as digits as its factorization.

16005661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2286530.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 16005661 is about 4000.7075624194. The cubic root of 16005661 is about 252.0139248625.

The spelling of 16005661 in words is "sixteen million, five thousand, six hundred sixty-one".