16661250725565 has 16 divisors (see below), whose sum is σ = 26867906684928. Its totient is φ = 8816031878976.

The previous prime is 16661250725551. The next prime is 16661250725573. The reversal of 16661250725565 is 56552705216661.

It is not a de Polignac number, because 16661250725565 - 2⁴ = 16661250725549 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4373029782 + ... + 4373033591.

It is an arithmetic number, because the mean of its divisors is an integer number (1679244167808).

Almost surely, 2^{16661250725565} is an apocalyptic number.

16661250725565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16661250725565 is a deficient number, since it is larger than the sum of its proper divisors (10206655959363).

16661250725565 is a wasteful number, since it uses less digits than its factorization.

16661250725565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8746063508.

The product of its (nonzero) digits is 22680000, while the sum is 57.

The spelling of 16661250725565 in words is "sixteen trillion, six hundred sixty-one billion, two hundred fifty million, seven hundred twenty-five thousand, five hundred sixty-five".