128637791 has 2 divisors, whose sum is σ = 128637792. Its totient is φ = 128637790.

The previous prime is 128637749. The next prime is 128637797. The reversal of 128637791 is 197736821.

It is a strong prime.

It is an emirp because it is prime and its reverse (197736821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 128637791 - 2⁶ = 128637727 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128637797) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64318895 + 64318896.

It is an arithmetic number, because the mean of its divisors is an integer number (64318896).

Almost surely, 2^128637791 is an apocalyptic number.

128637791 is a deficient number, since it is larger than the sum of its proper divisors (1).

128637791 is an equidigital number, since it uses as much as digits as its factorization.

128637791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 127008, while the sum is 44.

The square root of 128637791 is about 11341.8601208091. The cubic root of 128637791 is about 504.8040817643.

The spelling of 128637791 in words is "one hundred twenty-eight million, six hundred thirty-seven thousand, seven hundred ninety-one".