266339598561 has 9 divisors (see below), whose sum is σ = 384714989841. Its totient is φ = 177558700212.

The previous prime is 266339598541. The next prime is 266339598583. The reversal of 266339598561 is 165895933662.

The square root of 266339598561 is 516081.

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

266339598561 is a `hidden beast` number, since 2 + 6 + 6 + 3 + 39 + 598 + 5 + 6 + 1 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 266339598561 - 2¹⁷ = 266339467489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (266339598541) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1462230 + ... + 1634256.

Almost surely, 2^266339598561 is an apocalyptic number.

266339598561 is the 516081-st square number.

266339598561 is the 258041-st centered octagonal number.

It is an amenable number.

266339598561 is a deficient number, since it is larger than the sum of its proper divisors (118375391280).

266339598561 is an frugal number, since it uses more digits than its factorization.

266339598561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344060 (or 172030 counting only the distinct ones).

The product of its digits is 62985600, while the sum is 63.

It can be divided in two parts, 266339 and 598561, that added together give a square (864900 = 930²).

The spelling of 266339598561 in words is "two hundred sixty-six billion, three hundred thirty-nine million, five hundred ninety-eight thousand, five hundred sixty-one".