128745761 has 4 divisors (see below), whose sum is σ = 133185300. Its totient is φ = 124306224.

The previous prime is 128745733. The next prime is 128745769. The reversal of 128745761 is 167547821.

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 105165025 + 23580736 = 10255^2 + 4856^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128745761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128745769) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2219726 + ... + 2219783.

It is an arithmetic number, because the mean of its divisors is an integer number (33296325).

Almost surely, 2^128745761 is an apocalyptic number.

It is an amenable number.

128745761 is a deficient number, since it is larger than the sum of its proper divisors (4439539).

128745761 is an equidigital number, since it uses as much as digits as its factorization.

128745761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4439538.

The product of its digits is 94080, while the sum is 41.

The square root of 128745761 is about 11346.6189237147. The cubic root of 128745761 is about 504.9452752515.

The spelling of 128745761 in words is "one hundred twenty-eight million, seven hundred forty-five thousand, seven hundred sixty-one".