166966218225 has 27 divisors (see below), whose sum is σ = 299066027169. Its totient is φ = 89045380800.

The previous prime is 166966218217. The next prime is 166966218253. The reversal of 166966218225 is 522812669661.

The square root of 166966218225 is 408615.

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

166966218225 is a `hidden beast` number, since 1 + 6 + 6 + 9 + 6 + 621 + 8 + 2 + 2 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 52459779681 + 114506438544 = 229041^2 + 338388^2 .

It is not a de Polignac number, because 166966218225 - 2³ = 166966218217 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 6115605 + ... + 6142845.

Almost surely, 2^166966218225 is an apocalyptic number.

166966218225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

166966218225 is the 408615-th square number.

166966218225 is the 204308-th centered octagonal number.

It is an amenable number.

166966218225 is a deficient number, since it is larger than the sum of its proper divisors (132099808944).

166966218225 is an frugal number, since it uses more digits than its factorization.

166966218225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54498 (or 27249 counting only the distinct ones).

The product of its digits is 3732480, while the sum is 54.

The spelling of 166966218225 in words is "one hundred sixty-six billion, nine hundred sixty-six million, two hundred eighteen thousand, two hundred twenty-five".