320728129 has 4 divisors (see below), whose sum is σ = 325515184. Its totient is φ = 315941076.

The previous prime is 320728127. The next prime is 320728193. The reversal of 320728129 is 921827023.

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 320728129 - 2¹ = 320728127 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 320728094 and 320728103.

It is not an unprimeable number, because it can be changed into a prime (320728127) 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, 2393427 + ... + 2393560.

It is an arithmetic number, because the mean of its divisors is an integer number (81378796).

Almost surely, 2^320728129 is an apocalyptic number.

It is an amenable number.

320728129 is a deficient number, since it is larger than the sum of its proper divisors (4787055).

320728129 is an equidigital number, since it uses as much as digits as its factorization.

320728129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4787054.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 320728129 is about 17908.8840802547. The cubic root of 320728129 is about 684.5087703010.

The spelling of 320728129 in words is "three hundred twenty million, seven hundred twenty-eight thousand, one hundred twenty-nine".