665266121 has 8 divisors (see below), whose sum is σ = 716649864. Its totient is φ = 613912320.

The previous prime is 665266079. The next prime is 665266139. The reversal of 665266121 is 121662566.

It can be written as a sum of positive squares in 4 ways, for example, as 193600 + 665072521 = 440^2 + 25789^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665266121 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (665266181) 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 7 ways as a sum of consecutive naturals, for example, 64031 + ... + 73691.

It is an arithmetic number, because the mean of its divisors is an integer number (89581233).

Almost surely, 2^665266121 is an apocalyptic number.

It is an amenable number.

665266121 is a deficient number, since it is larger than the sum of its proper divisors (51383743).

665266121 is a wasteful number, since it uses less digits than its factorization.

665266121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14971.

The product of its digits is 25920, while the sum is 35.

The square root of 665266121 is about 25792.7532652100. The cubic root of 665266121 is about 872.9682911803.

The spelling of 665266121 in words is "six hundred sixty-five million, two hundred sixty-six thousand, one hundred twenty-one".