16561787 has 16 divisors (see below), whose sum is σ = 19219200. Its totient is φ = 14113440.

The previous prime is 16561777. The next prime is 16561789. The reversal of 16561787 is 78716561.

It is not a de Polignac number, because 16561787 - 2¹⁰ = 16560763 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16561789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22418 + ... + 23144.

It is an arithmetic number, because the mean of its divisors is an integer number (1201200).

Almost surely, 2^16561787 is an apocalyptic number.

16561787 is a deficient number, since it is larger than the sum of its proper divisors (2657413).

16561787 is a wasteful number, since it uses less digits than its factorization.

16561787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 866.

The product of its digits is 70560, while the sum is 41.

The square root of 16561787 is about 4069.6175495985. The cubic root of 16561787 is about 254.8995477722.

It can be divided in two parts, 1656 and 1787, that added together give a palindrome (3443).

The spelling of 16561787 in words is "sixteen million, five hundred sixty-one thousand, seven hundred eighty-seven".