266646721 has 4 divisors (see below), whose sum is σ = 290887344. Its totient is φ = 242406100.

The previous prime is 266646697. The next prime is 266646749. The reversal of 266646721 is 127646662.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 266646721 - 2⁵ = 266646689 is a prime.

It is a super-2 number, since 2×266646721² = 142200947640103682, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (266646761) 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, 12120295 + ... + 12120316.

It is an arithmetic number, because the mean of its divisors is an integer number (72721836).

Almost surely, 2^266646721 is an apocalyptic number.

It is an amenable number.

266646721 is a deficient number, since it is larger than the sum of its proper divisors (24240623).

266646721 is a wasteful number, since it uses less digits than its factorization.

266646721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24240622.

The product of its digits is 145152, while the sum is 40.

The square root of 266646721 is about 16329.3208983105. The cubic root of 266646721 is about 643.6435415624.

The spelling of 266646721 in words is "two hundred sixty-six million, six hundred forty-six thousand, seven hundred twenty-one".