665566250 has 20 divisors (see below), whose sum is σ = 1247539722. Its totient is φ = 266226000.

The previous prime is 665566229. The next prime is 665566259. The reversal of 665566250 is 52665566.

It can be written as a sum of positive squares in 5 ways, for example, as 7284601 + 658281649 = 2699^2 + 25657^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 665566198 and 665566207.

It is not an unprimeable number, because it can be changed into a prime (665566259) by changing a digit.

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 9 ways as a sum of consecutive naturals, for example, 264977 + ... + 267476.

Almost surely, 2^665566250 is an apocalyptic number.

665566250 is a deficient number, since it is larger than the sum of its proper divisors (581973472).

665566250 is an equidigital number, since it uses as much as digits as its factorization.

665566250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532475 (or 532460 counting only the distinct ones).

The product of its (nonzero) digits is 324000, while the sum is 41.

The square root of 665566250 is about 25798.5706968429. The cubic root of 665566250 is about 873.0995487837.

The spelling of 665566250 in words is "six hundred sixty-five million, five hundred sixty-six thousand, two hundred fifty".