666355625 has 20 divisors (see below), whose sum is σ = 896741076. Its totient is φ = 492072000.

The previous prime is 666355621. The next prime is 666355637. The reversal of 666355625 is 526553666.

It can be written as a sum of positive squares in 10 ways, for example, as 661672729 + 4682896 = 25723^2 + 2164^2 .

It is not a de Polignac number, because 666355625 - 2² = 666355621 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666355621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 32882 + ... + 49131.

Almost surely, 2^666355625 is an apocalyptic number.

666355625 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

666355625 is a deficient number, since it is larger than the sum of its proper divisors (230385451).

666355625 is an equidigital number, since it uses as much as digits as its factorization.

666355625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82046 (or 82031 counting only the distinct ones).

The product of its digits is 972000, while the sum is 44.

The square root of 666355625 is about 25813.8649760163. The cubic root of 666355625 is about 873.4445836399. Note that the first 3 decimals are identical.

The spelling of 666355625 in words is "six hundred sixty-six million, three hundred fifty-five thousand, six hundred twenty-five".