27664071561 has 96 divisors (see below), whose sum is σ = 48538828800. Its totient is φ = 15524036640.

The previous prime is 27664071551. The next prime is 27664071577. The reversal of 27664071561 is 16517046672.

27664071561 is a `hidden beast` number, since 27 + 6 + 64 + 0 + 7 + 1 + 561 = 666.

It is not a de Polignac number, because 27664071561 - 2¹³ = 27664063369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (27664071511) 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 95 ways as a sum of consecutive naturals, for example, 20972860 + ... + 20974178.

It is an arithmetic number, because the mean of its divisors is an integer number (505612800).

Almost surely, 2^27664071561 is an apocalyptic number.

27664071561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

27664071561 is a deficient number, since it is larger than the sum of its proper divisors (20874757239).

27664071561 is a wasteful number, since it uses less digits than its factorization.

27664071561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1616 (or 1603 counting only the distinct ones).

The product of its (nonzero) digits is 423360, while the sum is 45.

The spelling of 27664071561 in words is "twenty-seven billion, six hundred sixty-four million, seventy-one thousand, five hundred sixty-one".