128120505 has 8 divisors (see below), whose sum is σ = 204992832. Its totient is φ = 68330928.

The previous prime is 128120471. The next prime is 128120507. The reversal of 128120505 is 505021821.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 128120505 - 2²¹ = 126023353 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128120507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4270669 + ... + 4270698.

It is an arithmetic number, because the mean of its divisors is an integer number (25624104).

Almost surely, 2^128120505 is an apocalyptic number.

128120505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128120505 is a deficient number, since it is larger than the sum of its proper divisors (76872327).

128120505 is an equidigital number, since it uses as much as digits as its factorization.

128120505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8541375.

The product of its (nonzero) digits is 800, while the sum is 24.

The square root of 128120505 is about 11319.0328650464. The cubic root of 128120505 is about 504.1265232553.

The spelling of 128120505 in words is "one hundred twenty-eight million, one hundred twenty thousand, five hundred five".