27991808409601 has 4 divisors (see below), whose sum is σ = 28045535489604. Its totient is φ = 27938081329600.

The previous prime is 27991808409557. The next prime is 27991808409619. The reversal of 27991808409601 is 10690480819972.

It is a happy number.

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 17431752268225 + 10560056141376 = 4175135^2 + 3249624^2 .

It is a cyclic number.

It is not a de Polignac number, because 27991808409601 - 2¹³ = 27991808401409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27991808449601) 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 3 ways as a sum of consecutive naturals, for example, 26863539220 + ... + 26863540261.

It is an arithmetic number, because the mean of its divisors is an integer number (7011383872401).

Almost surely, 2^{27991808409601} is an apocalyptic number.

It is an amenable number.

27991808409601 is a deficient number, since it is larger than the sum of its proper divisors (53727080003).

27991808409601 is an equidigital number, since it uses as much as digits as its factorization.

27991808409601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53727080002.

The product of its (nonzero) digits is 15676416, while the sum is 64.

The spelling of 27991808409601 in words is "twenty-seven trillion, nine hundred ninety-one billion, eight hundred eight million, four hundred nine thousand, six hundred one".