27991817433389 has 2 divisors, whose sum is σ = 27991817433390. Its totient is φ = 27991817433388.

The previous prime is 27991817433373. The next prime is 27991817433509. The reversal of 27991817433389 is 98333471819972.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14855759536489 + 13136057896900 = 3854317^2 + 3624370^2 .

It is a cyclic number.

It is not a de Polignac number, because 27991817433389 - 2⁴ = 27991817433373 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27991817436389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13995908716694 + 13995908716695.

It is an arithmetic number, because the mean of its divisors is an integer number (13995908716695).

Almost surely, 2^{27991817433389} is an apocalyptic number.

It is an amenable number.

27991817433389 is a deficient number, since it is larger than the sum of its proper divisors (1).

27991817433389 is an equidigital number, since it uses as much as digits as its factorization.

27991817433389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 493807104, while the sum is 74.

The spelling of 27991817433389 in words is "twenty-seven trillion, nine hundred ninety-one billion, eight hundred seventeen million, four hundred thirty-three thousand, three hundred eighty-nine".