266990257521 has 27 divisors (see below), whose sum is σ = 417631668129. Its totient is φ = 164289295872.

The previous prime is 266990257493. The next prime is 266990257529. The reversal of 266990257521 is 125752099662.

The square root of 266990257521 is 516711.

It is a perfect power (a square), and thus also a powerful number.

266990257521 is a `hidden beast` number, since 2 + 6 + 6 + 9 + 90 + 25 + 7 + 521 = 666.

266990257521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 95564448225 + 171425809296 = 309135^2 + 414036^2 .

It is not a de Polignac number, because 266990257521 - 2¹⁷ = 266990126449 is a prime.

It is a super-2 number, since 2×266990257521² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (266990257529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 20145105 + ... + 20158353.

Almost surely, 2^266990257521 is an apocalyptic number.

266990257521 is the 516711-st square number.

266990257521 is the 258356-th centered octagonal number.

It is an amenable number.

266990257521 is a deficient number, since it is larger than the sum of its proper divisors (150641410608).

266990257521 is an frugal number, since it uses more digits than its factorization.

266990257521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26530 (or 13265 counting only the distinct ones).

The product of its (nonzero) digits is 4082400, while the sum is 54.

The spelling of 266990257521 in words is "two hundred sixty-six billion, nine hundred ninety million, two hundred fifty-seven thousand, five hundred twenty-one".