266666661 has 20 divisors (see below), whose sum is σ = 400136352. Its totient is φ = 176982408.

The previous prime is 266666657. The next prime is 266666671. The reversal of 266666661 is 166666662.

266666661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 266666661 - 2² = 266666657 is a prime.

It is a super-2 number, since 2×266666661² = 142222216177777842, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (266666671) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 11136 + ... + 25638.

Almost surely, 2^266666661 is an apocalyptic number.

It is an amenable number.

266666661 is a deficient number, since it is larger than the sum of its proper divisors (133469691).

266666661 is a wasteful number, since it uses less digits than its factorization.

266666661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14742 (or 14733 counting only the distinct ones).

The product of its digits is 559872, while the sum is 45.

The square root of 266666661 is about 16329.9314450490. The cubic root of 266666661 is about 643.6595851778.

Subtracting from 266666661 its reverse (166666662), we obtain a palindrome (99999999).

The spelling of 266666661 in words is "two hundred sixty-six million, six hundred sixty-six thousand, six hundred sixty-one".