6665906025 has 27 divisors (see below), whose sum is σ = 11941572279. Its totient is φ = 3554496720.

The previous prime is 6665905999. The next prime is 6665906033. The reversal of 6665906025 is 5206095666.

The square root of 6665906025 is 81645.

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

It can be written as a sum of positive squares in only one way, i.e., 2399726169 + 4266179856 = 48987^2 + 65316^2 .

It is a de Polignac number, because none of the positive numbers 2^k-6665906025 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1221954 + ... + 1227396.

Almost surely, 2^6665906025 is an apocalyptic number.

6665906025 is the 81645-th square number.

6665906025 is the 40823-rd centered octagonal number.

It is an amenable number.

6665906025 is a deficient number, since it is larger than the sum of its proper divisors (5275666254).

6665906025 is an frugal number, since it uses more digits than its factorization.

6665906025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10902 (or 5451 counting only the distinct ones).

The product of its (nonzero) digits is 583200, while the sum is 45.

The cubic root of 6665906025 is about 1882.0004759182. Note that the first 3 decimals are identical.

The spelling of 6665906025 in words is "six billion, six hundred sixty-five million, nine hundred six thousand, twenty-five".