3128405 has 18 divisors (see below), whose sum is σ = 4405986. Its totient is φ = 2126208.

The previous prime is 3128401. The next prime is 3128443. The reversal of 3128405 is 5048213.

It can be written as a sum of positive squares in 3 ways, for example, as 329476 + 2798929 = 574^2 + 1673^2 .

It is not a de Polignac number, because 3128405 - 2² = 3128401 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 (3128401) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 27629 + ... + 27741.

It is an arithmetic number, because the mean of its divisors is an integer number (244777).

Almost surely, 2^3128405 is an apocalyptic number.

3128405 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

It is an amenable number.

3128405 is a deficient number, since it is larger than the sum of its proper divisors (1277581).

3128405 is an equidigital number, since it uses as much as digits as its factorization.

3128405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245 (or 125 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 3128405 is about 1768.7297702023. The cubic root of 3128405 is about 146.2539677985.

The spelling of 3128405 in words is "three million, one hundred twenty-eight thousand, four hundred five".