27771641561 has 16 divisors (see below), whose sum is σ = 28553472000. Its totient is φ = 26999900928.

The previous prime is 27771641549. The next prime is 27771641591. The reversal of 27771641561 is 16514617772.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27771641561 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (27771641501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6856865 + ... + 6860913.

It is an arithmetic number, because the mean of its divisors is an integer number (1784592000).

Almost surely, 2^27771641561 is an apocalyptic number.

It is an amenable number.

27771641561 is a deficient number, since it is larger than the sum of its proper divisors (781830439).

27771641561 is a wasteful number, since it uses less digits than its factorization.

27771641561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5248.

The product of its digits is 493920, while the sum is 47.

The spelling of 27771641561 in words is "twenty-seven billion, seven hundred seventy-one million, six hundred forty-one thousand, five hundred sixty-one".