666025 has 6 divisors (see below), whose sum is σ = 825902. Its totient is φ = 532800.

The previous prime is 666023. The next prime is 666031. The reversal of 666025 is 520666.

666025 = T₉₄ + T₉₅ + ... + T₁₆₈.

It can be written as a sum of positive squares in 3 ways, for example, as 169 + 665856 = 13^2 + 816^2 .

It is not a de Polignac number, because 666025 - 2¹ = 666023 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25), and also a Moran number because the ratio is a prime number: 26641 = 666025 / (6 + 6 + 6 + 0 + 2 + 5).

It is an Ulam number.

It is a Duffinian number.

666025 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (666023) 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, 13296 + ... + 13345.

2⁶⁶⁶⁰²⁵ is an apocalyptic number.

It is an amenable number.

666025 is a deficient number, since it is larger than the sum of its proper divisors (159877).

666025 is a wasteful number, since it uses less digits than its factorization.

666025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26651 (or 26646 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 666025 is about 816.1035473517. The cubic root of 666025 is about 87.3300101035.

The spelling of 666025 in words is "six hundred sixty-six thousand, twenty-five".