666001249 has 9 divisors (see below), whose sum is σ = 674548051. Its totient is φ = 657562360.

The previous prime is 666001247. The next prime is 666001261. The reversal of 666001249 is 942100666.

The square root of 666001249 is 25807.

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., 652547025 + 13454224 = 25545^2 + 3668^2 .

It is not a de Polignac number, because 666001249 - 2¹ = 666001247 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666001247) 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 8 ways as a sum of consecutive naturals, for example, 3380619 + ... + 3380815.

Almost surely, 2^666001249 is an apocalyptic number.

666001249 is the 25807-th square number.

666001249 is the 12904-th centered octagonal number.

It is an amenable number.

666001249 is a deficient number, since it is larger than the sum of its proper divisors (8546802).

666001249 is an frugal number, since it uses more digits than its factorization.

666001249 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 656 (or 328 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 34.

The cubic root of 666001249 is about 873.2897200443.

The spelling of 666001249 in words is "six hundred sixty-six million, one thousand, two hundred forty-nine".