27731816557 has 4 divisors (see below), whose sum is σ = 27839722716. Its totient is φ = 27623910400.

The previous prime is 27731816543. The next prime is 27731816569. The reversal of 27731816557 is 75561813772.

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 23808798601 + 3923017956 = 154301^2 + 62634^2 .

It is a cyclic number.

It is not a de Polignac number, because 27731816557 - 2¹⁵ = 27731783789 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 (27731814557) 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, 53952694 + ... + 53953207.

It is an arithmetic number, because the mean of its divisors is an integer number (6959930679).

Almost surely, 2^27731816557 is an apocalyptic number.

It is an amenable number.

27731816557 is a deficient number, since it is larger than the sum of its proper divisors (107906159).

27731816557 is a wasteful number, since it uses less digits than its factorization.

27731816557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107906158.

The product of its digits is 2469600, while the sum is 52.

The spelling of 27731816557 in words is "twenty-seven billion, seven hundred thirty-one million, eight hundred sixteen thousand, five hundred fifty-seven".