266240221 has 8 divisors (see below), whose sum is σ = 287232120. Its totient is φ = 245321472.

The previous prime is 266240119. The next prime is 266240231. The reversal of 266240221 is 122042662.

It can be written as a sum of positive squares in 4 ways, for example, as 14668900 + 251571321 = 3830^2 + 15861^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 266240221 - 2²¹ = 264143069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (266240231) 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, 10600 + ... + 25393.

It is an arithmetic number, because the mean of its divisors is an integer number (35904015).

Almost surely, 2^266240221 is an apocalyptic number.

It is an amenable number.

266240221 is a deficient number, since it is larger than the sum of its proper divisors (20991899).

266240221 is a wasteful number, since it uses less digits than its factorization.

266240221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36575.

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 266240221 is about 16316.8692156308. The cubic root of 266240221 is about 643.3162993751.

Adding to 266240221 its reverse (122042662), we get a palindrome (388282883).

The spelling of 266240221 in words is "two hundred sixty-six million, two hundred forty thousand, two hundred twenty-one".