16566405934225 has 135 divisors (see below), whose sum is σ = 24684816566067. Its totient is φ = 11028182538240.

The previous prime is 16566405934193. The next prime is 16566405934297. The reversal of 16566405934225 is 52243950466561.

The square root of 16566405934225 is 4070185.

It is a perfect power (a square), and thus also a powerful number.

16566405934225 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 13 ways, for example, as 2057437378129 + 14508968556096 = 1434377^2 + 3809064^2 .

It is not a de Polignac number, because 16566405934225 - 2⁵ = 16566405934193 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16566405934225.

It is an unprimeable number.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 36896226801 + ... + 36896227249.

Almost surely, 2^{16566405934225} is an apocalyptic number.

16566405934225 is the 4070185-th square number.

16566405934225 is the 2035093-rd centered octagonal number.

It is an amenable number.

16566405934225 is a deficient number, since it is larger than the sum of its proper divisors (8118410631842).

16566405934225 is an frugal number, since it uses more digits than its factorization.

16566405934225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1010 (or 498 counting only the distinct ones).

The product of its (nonzero) digits is 46656000, while the sum is 58.

The spelling of 16566405934225 in words is "sixteen trillion, five hundred sixty-six billion, four hundred five million, nine hundred thirty-four thousand, two hundred twenty-five".