128498561 has 4 divisors (see below), whose sum is σ = 128525124. Its totient is φ = 128472000.

The previous prime is 128498527. The next prime is 128498567. The reversal of 128498561 is 165894821.

128498561 is nontrivially palindromic in base 3.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 165894821 = 353 ⋅469957.

It can be written as a sum of positive squares in 2 ways, for example, as 8814961 + 119683600 = 2969^2 + 10940^2 .

It is a cyclic number.

It is not a de Polignac number, because 128498561 - 2¹⁴ = 128482177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128498567) 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, 3740 + ... + 16461.

It is an arithmetic number, because the mean of its divisors is an integer number (32131281).

Almost surely, 2^128498561 is an apocalyptic number.

It is an amenable number.

128498561 is a deficient number, since it is larger than the sum of its proper divisors (26563).

128498561 is an equidigital number, since it uses as much as digits as its factorization.

128498561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26562.

The product of its digits is 138240, while the sum is 44.

The square root of 128498561 is about 11335.7205770079. The cubic root of 128498561 is about 504.6218925749.

The spelling of 128498561 in words is "one hundred twenty-eight million, four hundred ninety-eight thousand, five hundred sixty-one".