128752561 has 4 divisors (see below), whose sum is σ = 147145792. Its totient is φ = 110359332.

The previous prime is 128752511. The next prime is 128752567. The reversal of 128752561 is 165257821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 165257821 = 2153 ⋅76757.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128752561 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 128752561.

It is not an unprimeable number, because it can be changed into a prime (128752567) 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, 9196605 + ... + 9196618.

It is an arithmetic number, because the mean of its divisors is an integer number (36786448).

Almost surely, 2^128752561 is an apocalyptic number.

It is an amenable number.

128752561 is a deficient number, since it is larger than the sum of its proper divisors (18393231).

128752561 is an equidigital number, since it uses as much as digits as its factorization.

128752561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18393230.

The product of its digits is 33600, while the sum is 37.

The square root of 128752561 is about 11346.9185684925. The cubic root of 128752561 is about 504.9541650391.

The spelling of 128752561 in words is "one hundred twenty-eight million, seven hundred fifty-two thousand, five hundred sixty-one".