128305381 has 4 divisors (see below), whose sum is σ = 131773132. Its totient is φ = 124837632.

The previous prime is 128305369. The next prime is 128305391. The reversal of 128305381 is 183503821.

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 63760225 + 64545156 = 7985^2 + 8034^2 .

It is a cyclic number.

It is not a de Polignac number, because 128305381 - 2¹⁷ = 128174309 is a prime.

It is a super-2 number, since 2×128305381² = 32924541587110322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128305391) 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, 1733820 + ... + 1733893.

It is an arithmetic number, because the mean of its divisors is an integer number (32943283).

Almost surely, 2^128305381 is an apocalyptic number.

It is an amenable number.

128305381 is a deficient number, since it is larger than the sum of its proper divisors (3467751).

128305381 is an equidigital number, since it uses as much as digits as its factorization.

128305381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3467750.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 128305381 is about 11327.1965198808. The cubic root of 128305381 is about 504.3688890964.

The spelling of 128305381 in words is "one hundred twenty-eight million, three hundred five thousand, three hundred eighty-one".