128308813 has 4 divisors (see below), whose sum is σ = 130729788. Its totient is φ = 125887840.

The previous prime is 128308801. The next prime is 128308853. The reversal of 128308813 is 318803821.

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 34257609 + 94051204 = 5853^2 + 9698^2 .

It is a cyclic number.

It is not a de Polignac number, because 128308813 - 2⁵ = 128308781 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128308853) 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, 1210408 + ... + 1210513.

It is an arithmetic number, because the mean of its divisors is an integer number (32682447).

Almost surely, 2^128308813 is an apocalyptic number.

It is an amenable number.

128308813 is a deficient number, since it is larger than the sum of its proper divisors (2420975).

128308813 is an equidigital number, since it uses as much as digits as its factorization.

128308813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2420974.

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 128308813 is about 11327.3480126639. The cubic root of 128308813 is about 504.3733861242.

The spelling of 128308813 in words is "one hundred twenty-eight million, three hundred eight thousand, eight hundred thirteen".