1666384083225 has 81 divisors (see below), whose sum is σ = 3060709809469. Its totient is φ = 866648553600.

The previous prime is 1666384083191. The next prime is 1666384083229. The reversal of 1666384083225 is 5223804836661.

The square root of 1666384083225 is 1290885.

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

It can be written as a sum of positive squares in 4 ways, for example, as 701407925001 + 964976158224 = 837501^2 + 982332^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1666384083225 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666384083229) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 793893226 + ... + 793895324.

Almost surely, 2^{1666384083225} is an apocalyptic number.

1666384083225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1666384083225 is the 1290885-th square number.

1666384083225 is the 645443-rd centered octagonal number.

It is an amenable number.

1666384083225 is a deficient number, since it is larger than the sum of its proper divisors (1394325726244).

1666384083225 is an frugal number, since it uses more digits than its factorization.

1666384083225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4296 (or 2148 counting only the distinct ones).

The product of its (nonzero) digits is 9953280, while the sum is 54.

The spelling of 1666384083225 in words is "one trillion, six hundred sixty-six billion, three hundred eighty-four million, eighty-three thousand, two hundred twenty-five".