666651025 has 6 divisors (see below), whose sum is σ = 826647302. Its totient is φ = 533320800.

The previous prime is 666651023. The next prime is 666651049. The reversal of 666651025 is 520156666.

666651025 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 804609 + 665846416 = 897^2 + 25804^2 .

It is not a de Polignac number, because 666651025 - 2¹ = 666651023 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666651023) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13332996 + ... + 13333045.

Almost surely, 2^666651025 is an apocalyptic number.

It is an amenable number.

666651025 is a deficient number, since it is larger than the sum of its proper divisors (159996277).

666651025 is a wasteful number, since it uses less digits than its factorization.

666651025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26666051 (or 26666046 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 37.

The square root of 666651025 is about 25819.5860733669. The cubic root of 666651025 is about 873.5736325556.

The spelling of 666651025 in words is "six hundred sixty-six million, six hundred fifty-one thousand, twenty-five".