26645513661 has 12 divisors (see below), whose sum is σ = 41448576988. Its totient is φ = 16397239104.

The previous prime is 26645513659. The next prime is 26645513707. The reversal of 26645513661 is 16631554662.

26645513661 is a `hidden beast` number, since 2 + 6 + 6 + 4 + 551 + 36 + 61 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 10215144900 + 16430368761 = 101070^2 + 128181^2 .

It is not a de Polignac number, because 26645513661 - 2¹ = 26645513659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26645513161) 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 11 ways as a sum of consecutive naturals, for example, 113869600 + ... + 113869833.

Almost surely, 2^26645513661 is an apocalyptic number.

It is an amenable number.

26645513661 is a deficient number, since it is larger than the sum of its proper divisors (14803063327).

26645513661 is a wasteful number, since it uses less digits than its factorization.

26645513661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227739452 (or 227739449 counting only the distinct ones).

The product of its digits is 777600, while the sum is 45.

The spelling of 26645513661 in words is "twenty-six billion, six hundred forty-five million, five hundred thirteen thousand, six hundred sixty-one".