128249987 has 2 divisors, whose sum is σ = 128249988. Its totient is φ = 128249986.

The previous prime is 128249959. The next prime is 128250013. The reversal of 128249987 is 789942821.

It is a strong prime.

It is an emirp because it is prime and its reverse (789942821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 128249987 - 2⁶ = 128249923 is a prime.

It is not a weakly prime, because it can be changed into another prime (128249087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64124993 + 64124994.

It is an arithmetic number, because the mean of its divisors is an integer number (64124994).

Almost surely, 2^128249987 is an apocalyptic number.

128249987 is a deficient number, since it is larger than the sum of its proper divisors (1).

128249987 is an equidigital number, since it uses as much as digits as its factorization.

128249987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 580608, while the sum is 50.

The square root of 128249987 is about 11324.7510789421. The cubic root of 128249987 is about 504.2962939806.

The spelling of 128249987 in words is "one hundred twenty-eight million, two hundred forty-nine thousand, nine hundred eighty-seven".