128923505 has 8 divisors (see below), whose sum is σ = 155096424. Its totient is φ = 102880000.

The previous prime is 128923489. The next prime is 128923523. The reversal of 128923505 is 505329821.

It can be written as a sum of positive squares in 4 ways, for example, as 39488656 + 89434849 = 6284^2 + 9457^2 .

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

It is not a de Polignac number, because 128923505 - 2⁴ = 128923489 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30146 + ... + 34155.

It is an arithmetic number, because the mean of its divisors is an integer number (19387053).

Almost surely, 2^128923505 is an apocalyptic number.

It is an amenable number.

128923505 is a deficient number, since it is larger than the sum of its proper divisors (26172919).

128923505 is an equidigital number, since it uses as much as digits as its factorization.

128923505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64707.

The product of its (nonzero) digits is 21600, while the sum is 35.

The square root of 128923505 is about 11354.4486876290. The cubic root of 128923505 is about 505.1775410781.

The spelling of 128923505 in words is "one hundred twenty-eight million, nine hundred twenty-three thousand, five hundred five".