655561255661 has 4 divisors (see below), whose sum is σ = 705989044572. Its totient is φ = 605133466752.

The previous prime is 655561255637. The next prime is 655561255663. The reversal of 655561255661 is 166552165556.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 27514515625 + 628046740036 = 165875^2 + 792494^2 .

It is a cyclic number.

It is not a de Polignac number, because 655561255661 - 2¹⁰ = 655561254637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (655561255663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25213894436 + ... + 25213894461.

It is an arithmetic number, because the mean of its divisors is an integer number (176497261143).

Almost surely, 2^655561255661 is an apocalyptic number.

It is an amenable number.

655561255661 is a deficient number, since it is larger than the sum of its proper divisors (50427788911).

655561255661 is a wasteful number, since it uses less digits than its factorization.

655561255661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50427788910.

The product of its digits is 8100000, while the sum is 53.

The spelling of 655561255661 in words is "six hundred fifty-five billion, five hundred sixty-one million, two hundred fifty-five thousand, six hundred sixty-one".