663779522238561 has 27 divisors (see below), whose sum is σ = 992997874283961. Its totient is φ = 427258939351104.

The previous prime is 663779522238463. The next prime is 663779522238587. The reversal of 663779522238561 is 165832225977366.

The square root of 663779522238561 is 25763919.

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

663779522238561 is a `hidden beast` number, since 6 + 6 + 3 + 7 + 7 + 9 + 5 + 2 + 22 + 38 + 561 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 41923358780625 + 621856163457936 = 6474825^2 + 24937044^2 .

It is a de Polignac number, because none of the positive numbers 2^k-663779522238561 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 663779522238561.

It is not an unprimeable number, because it can be changed into a prime (663779522338561) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2241312885 + ... + 2241609021.

Almost surely, 2^{663779522238561} is an apocalyptic number.

663779522238561 is the 25763919-th square number.

663779522238561 is the 12881960-th centered octagonal number.

It is an amenable number.

663779522238561 is a deficient number, since it is larger than the sum of its proper divisors (329218352045400).

663779522238561 is an frugal number, since it uses more digits than its factorization.

663779522238561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592338 (or 296169 counting only the distinct ones).

The product of its digits is 1371686400, while the sum is 72.

The spelling of 663779522238561 in words is "six hundred sixty-three trillion, seven hundred seventy-nine billion, five hundred twenty-two million, two hundred thirty-eight thousand, five hundred sixty-one".