128142505 has 4 divisors (see below), whose sum is σ = 153771012. Its totient is φ = 102514000.

The previous prime is 128142493. The next prime is 128142523. The reversal of 128142505 is 505241821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 60047001 + 68095504 = 7749^2 + 8252^2 .

It is a de Polignac number, because none of the positive numbers 2^k-128142505 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12814246 + ... + 12814255.

It is an arithmetic number, because the mean of its divisors is an integer number (38442753).

Almost surely, 2^128142505 is an apocalyptic number.

It is an amenable number.

128142505 is a deficient number, since it is larger than the sum of its proper divisors (25628507).

128142505 is an equidigital number, since it uses as much as digits as its factorization.

128142505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25628506.

The product of its (nonzero) digits is 3200, while the sum is 28.

The square root of 128142505 is about 11320.0046378082. The cubic root of 128142505 is about 504.1553766871.

The spelling of 128142505 in words is "one hundred twenty-eight million, one hundred forty-two thousand, five hundred five".