128730813 has 4 divisors (see below), whose sum is σ = 171641088. Its totient is φ = 85820540.

The previous prime is 128730809. The next prime is 128730821. The reversal of 128730813 is 318037821.

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.

It is a cyclic number.

It is not a de Polignac number, because 128730813 - 2² = 128730809 is a prime.

It is a super-3 number, since 3×128730813³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128730803) 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, 21455133 + ... + 21455138.

It is an arithmetic number, because the mean of its divisors is an integer number (42910272).

Almost surely, 2^128730813 is an apocalyptic number.

It is an amenable number.

128730813 is a deficient number, since it is larger than the sum of its proper divisors (42910275).

128730813 is an equidigital number, since it uses as much as digits as its factorization.

128730813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42910274.

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 128730813 is about 11345.9602061703. The cubic root of 128730813 is about 504.9257323062.

The spelling of 128730813 in words is "one hundred twenty-eight million, seven hundred thirty thousand, eight hundred thirteen".