266665061 has 4 divisors (see below), whose sum is σ = 287177772. Its totient is φ = 246152352.

The previous prime is 266665051. The next prime is 266665081. The reversal of 266665061 is 160566662.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 160566662 = 2 ⋅80283331.

It can be written as a sum of positive squares in 2 ways, for example, as 10857025 + 255808036 = 3295^2 + 15994^2 .

It is a cyclic number.

It is not a de Polignac number, because 266665061 - 2²⁶ = 199556197 is a prime.

It is a super-2 number, since 2×266665061² = 142220509516267442, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (266665001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10256336 + ... + 10256361.

It is an arithmetic number, because the mean of its divisors is an integer number (71794443).

Almost surely, 2^266665061 is an apocalyptic number.

It is an amenable number.

266665061 is a deficient number, since it is larger than the sum of its proper divisors (20512711).

266665061 is a wasteful number, since it uses less digits than its factorization.

266665061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20512710.

The product of its (nonzero) digits is 77760, while the sum is 38.

The square root of 266665061 is about 16329.8824551801. The cubic root of 266665061 is about 643.6582978561.

The spelling of 266665061 in words is "two hundred sixty-six million, six hundred sixty-five thousand, sixty-one".