128508949 has 2 divisors, whose sum is σ = 128508950. Its totient is φ = 128508948.

The previous prime is 128508943. The next prime is 128508953. The reversal of 128508949 is 949805821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 109307025 + 19201924 = 10455^2 + 4382^2 .

It is an emirp because it is prime and its reverse (949805821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 128508949 - 2¹⁷ = 128377877 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 128508899 and 128508908.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128508943) 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, 64254474 + 64254475.

It is an arithmetic number, because the mean of its divisors is an integer number (64254475).

Almost surely, 2^128508949 is an apocalyptic number.

It is an amenable number.

128508949 is a deficient number, since it is larger than the sum of its proper divisors (1).

128508949 is an equidigital number, since it uses as much as digits as its factorization.

128508949 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 207360, while the sum is 46.

The square root of 128508949 is about 11336.1787653512. The cubic root of 128508949 is about 504.6354903172.

The spelling of 128508949 in words is "one hundred twenty-eight million, five hundred eight thousand, nine hundred forty-nine".