16561745 has 8 divisors (see below), whose sum is σ = 20359080. Its totient is φ = 12926080.

The previous prime is 16561717. The next prime is 16561763. The reversal of 16561745 is 54716561.

It can be written as a sum of positive squares in 4 ways, for example, as 625681 + 15936064 = 791^2 + 3992^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 16561745 - 2¹⁰ = 16560721 is a prime.

It is a Curzon number.

It is a nialpdrome in base 16.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40190 + ... + 40599.

It is an arithmetic number, because the mean of its divisors is an integer number (2544885).

Almost surely, 2^16561745 is an apocalyptic number.

It is an amenable number.

16561745 is a deficient number, since it is larger than the sum of its proper divisors (3797335).

16561745 is an equidigital number, since it uses as much as digits as its factorization.

16561745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80835.

The product of its digits is 25200, while the sum is 35.

The square root of 16561745 is about 4069.6123894052. The cubic root of 16561745 is about 254.8993323005.

The spelling of 16561745 in words is "sixteen million, five hundred sixty-one thousand, seven hundred forty-five".