16561005 has 16 divisors (see below), whose sum is σ = 26948160. Its totient is φ = 8682368.

The previous prime is 16561003. The next prime is 16561033. The reversal of 16561005 is 50016561.

It is a cyclic number.

It is not a de Polignac number, because 16561005 - 2¹ = 16561003 is a prime.

It is a super-2 number, since 2×16561005² = 548533773220050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16561003) 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, 8472 + ... + 10241.

It is an arithmetic number, because the mean of its divisors is an integer number (1684260).

Almost surely, 2^16561005 is an apocalyptic number.

16561005 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16561005 is a deficient number, since it is larger than the sum of its proper divisors (10387155).

16561005 is a wasteful number, since it uses less digits than its factorization.

16561005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18780.

The product of its (nonzero) digits is 900, while the sum is 24.

The square root of 16561005 is about 4069.5214706400. The cubic root of 16561005 is about 254.8955358343.

Adding to 16561005 its reverse (50016561), we get a palindrome (66577566).

The spelling of 16561005 in words is "sixteen million, five hundred sixty-one thousand, five".