128520949 has 2 divisors, whose sum is σ = 128520950. Its totient is φ = 128520948.

The previous prime is 128520893. The next prime is 128520971. The reversal of 128520949 is 949025821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125596849 + 2924100 = 11207^2 + 1710^2 .

It is an emirp because it is prime and its reverse (949025821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 128520949 - 2¹⁵ = 128488181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128520979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64260474 + 64260475.

It is an arithmetic number, because the mean of its divisors is an integer number (64260475).

Almost surely, 2^128520949 is an apocalyptic number.

It is an amenable number.

128520949 is a deficient number, since it is larger than the sum of its proper divisors (1).

128520949 is an equidigital number, since it uses as much as digits as its factorization.

128520949 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 40.

The square root of 128520949 is about 11336.7080318759. The cubic root of 128520949 is about 504.6511972322.

The spelling of 128520949 in words is "one hundred twenty-eight million, five hundred twenty thousand, nine hundred forty-nine".