3966809139225 has 135 divisors (see below), whose sum is σ = 7457660455999. Its totient is φ = 2015585220000.

The previous prime is 3966809139211. The next prime is 3966809139287. The reversal of 3966809139225 is 5229319086693.

The square root of 3966809139225 is 1991685.

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

3966809139225 is a `hidden beast` number, since 3 + 9 + 66 + 80 + 91 + 392 + 25 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1428051290121 + 2538757849104 = 1195011^2 + 1593348^2 .

It is not a de Polignac number, because 3966809139225 - 2¹⁵ = 3966809106457 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 15804020350 + ... + 15804020600.

Almost surely, 2^{3966809139225} is an apocalyptic number.

3966809139225 is the 1991685-th square number.

3966809139225 is the 995843-rd centered octagonal number.

It is an amenable number.

3966809139225 is a deficient number, since it is larger than the sum of its proper divisors (3490851316774).

3966809139225 is an frugal number, since it uses more digits than its factorization.

3966809139225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610 (or 282 counting only the distinct ones).

The product of its (nonzero) digits is 37791360, while the sum is 63.

The spelling of 3966809139225 in words is "three trillion, nine hundred sixty-six billion, eight hundred nine million, one hundred thirty-nine thousand, two hundred twenty-five".