128538181 has 4 divisors (see below), whose sum is σ = 130299052. Its totient is φ = 126777312.

The previous prime is 128538143. The next prime is 128538209. The reversal of 128538181 is 181835821.

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 48525156 + 80013025 = 6966^2 + 8945^2 .

It is a cyclic number.

It is not a de Polignac number, because 128538181 - 2¹⁵ = 128505413 is a prime.

It is a super-2 number, since 2×128538181² = 33044127949577522, which contains 22 as substring.

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 128538181.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128578181) 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, 880326 + ... + 880471.

It is an arithmetic number, because the mean of its divisors is an integer number (32574763).

Almost surely, 2^128538181 is an apocalyptic number.

It is an amenable number.

128538181 is a deficient number, since it is larger than the sum of its proper divisors (1760871).

128538181 is an equidigital number, since it uses as much as digits as its factorization.

128538181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1760870.

The product of its digits is 15360, while the sum is 37.

The square root of 128538181 is about 11337.4680153904. The cubic root of 128538181 is about 504.6737506521.

The spelling of 128538181 in words is "one hundred twenty-eight million, five hundred thirty-eight thousand, one hundred eighty-one".