266897257641 has 81 divisors (see below), whose sum is σ = 456040685061. Its totient is φ = 149977142784.

The previous prime is 266897257607. The next prime is 266897257663. The reversal of 266897257641 is 146752798662.

The square root of 266897257641 is 516621.

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

266897257641 is a `hidden beast` number, since 266 + 89 + 7 + 257 + 6 + 41 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 7775536041 + 259121721600 = 88179^2 + 509040^2 .

It is not a de Polignac number, because 266897257641 - 2⁹ = 266897257129 is a prime.

It is a super-2 number, since 2×266897257641² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

Its product of digits (60963840) is a multiple of the sum of its prime divisors (420).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (266897259641) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 791979825 + ... + 791980161.

Almost surely, 2^266897257641 is an apocalyptic number.

266897257641 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

266897257641 is the 516621-st square number.

266897257641 is the 258311-st centered octagonal number.

It is an amenable number.

266897257641 is a deficient number, since it is larger than the sum of its proper divisors (189143427420).

266897257641 is an frugal number, since it uses more digits than its factorization.

266897257641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840 (or 420 counting only the distinct ones).

The product of its digits is 60963840, while the sum is 63.

The spelling of 266897257641 in words is "two hundred sixty-six billion, eight hundred ninety-seven million, two hundred fifty-seven thousand, six hundred forty-one".