27138128197 has 2 divisors, whose sum is σ = 27138128198. Its totient is φ = 27138128196.

The previous prime is 27138128183. The next prime is 27138128257. The reversal of 27138128197 is 79182183172.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15316785121 + 11821343076 = 123761^2 + 108726^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27138128197 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 27138128197.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27138120197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13569064098 + 13569064099.

It is an arithmetic number, because the mean of its divisors is an integer number (13569064099).

Almost surely, 2^27138128197 is an apocalyptic number.

It is an amenable number.

27138128197 is a deficient number, since it is larger than the sum of its proper divisors (1).

27138128197 is an equidigital number, since it uses as much as digits as its factorization.

27138128197 is an evil number, because the sum of its binary digits is even.

The product of its digits is 338688, while the sum is 49.

The spelling of 27138128197 in words is "twenty-seven billion, one hundred thirty-eight million, one hundred twenty-eight thousand, one hundred ninety-seven".