27755561608661 has 4 divisors (see below), whose sum is σ = 27765506277024. Its totient is φ = 27745616940300.

The previous prime is 27755561608631. The next prime is 27755561608681. The reversal of 27755561608661 is 16680616555772.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 27755561608661 - 2¹⁸ = 27755561346517 is a prime.

It is a super-2 number, since 2×27755561608661² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27755561608631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4972329995 + ... + 4972335576.

It is an arithmetic number, because the mean of its divisors is an integer number (6941376569256).

Almost surely, 2^{27755561608661} is an apocalyptic number.

It is an amenable number.

27755561608661 is a deficient number, since it is larger than the sum of its proper divisors (9944668363).

27755561608661 is an equidigital number, since it uses as much as digits as its factorization.

27755561608661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9944668362.

The product of its (nonzero) digits is 127008000, while the sum is 65.

The spelling of 27755561608661 in words is "twenty-seven trillion, seven hundred fifty-five billion, five hundred sixty-one million, six hundred eight thousand, six hundred sixty-one".