128785105 has 4 divisors (see below), whose sum is σ = 154542132. Its totient is φ = 103028080.

The previous prime is 128785103. The next prime is 128785109. The reversal of 128785105 is 501587821.

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 39841344 + 88943761 = 6312^2 + 9431^2 .

It is not a de Polignac number, because 128785105 - 2¹ = 128785103 is a prime.

It is a super-2 number, since 2×128785105² = 33171206539722050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128785103) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12878506 + ... + 12878515.

It is an arithmetic number, because the mean of its divisors is an integer number (38635533).

Almost surely, 2^128785105 is an apocalyptic number.

It is an amenable number.

128785105 is a deficient number, since it is larger than the sum of its proper divisors (25757027).

128785105 is an equidigital number, since it uses as much as digits as its factorization.

128785105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25757026.

The product of its (nonzero) digits is 22400, while the sum is 37.

The square root of 128785105 is about 11348.3525236045. The cubic root of 128785105 is about 504.9967061838.

The spelling of 128785105 in words is "one hundred twenty-eight million, seven hundred eighty-five thousand, one hundred five".