27889771391 has 4 divisors (see below), whose sum is σ = 27894174672. Its totient is φ = 27885368112.

The previous prime is 27889771367. The next prime is 27889771417. The reversal of 27889771391 is 19317798872.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27889771391 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 (27889771331) 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, 2192126 + ... + 2204811.

It is an arithmetic number, because the mean of its divisors is an integer number (6973543668).

Almost surely, 2^27889771391 is an apocalyptic number.

27889771391 is a deficient number, since it is larger than the sum of its proper divisors (4403281).

27889771391 is an equidigital number, since it uses as much as digits as its factorization.

27889771391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4403280.

The product of its digits is 10668672, while the sum is 62.

The spelling of 27889771391 in words is "twenty-seven billion, eight hundred eighty-nine million, seven hundred seventy-one thousand, three hundred ninety-one".