16561605 has 8 divisors (see below), whose sum is σ = 26498592. Its totient is φ = 8832848.

The previous prime is 16561603. The next prime is 16561613. The reversal of 16561605 is 50616561.

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 16561605 - 2¹ = 16561603 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16561603) 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, 552039 + ... + 552068.

It is an arithmetic number, because the mean of its divisors is an integer number (3312324).

Almost surely, 2^16561605 is an apocalyptic number.

16561605 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16561605 is a deficient number, since it is larger than the sum of its proper divisors (9936987).

16561605 is a wasteful number, since it uses less digits than its factorization.

16561605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1104115.

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 16561605 is about 4069.5951887135. The cubic root of 16561605 is about 254.8986140588.

The spelling of 16561605 in words is "sixteen million, five hundred sixty-one thousand, six hundred five".