204128819 has 4 divisors (see below), whose sum is σ = 204174696. Its totient is φ = 204082944.

The previous prime is 204128807. The next prime is 204128857. The reversal of 204128819 is 918821402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 918821402 = 2 ⋅459410701.

It is a cyclic number.

It is not a de Polignac number, because 204128819 - 2⁸ = 204128563 is a prime.

It is a super-2 number, since 2×204128819² = 83337149492669522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204128879) 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, 15449 + ... + 25434.

It is an arithmetic number, because the mean of its divisors is an integer number (51043674).

Almost surely, 2^204128819 is an apocalyptic number.

204128819 is a deficient number, since it is larger than the sum of its proper divisors (45877).

204128819 is an equidigital number, since it uses as much as digits as its factorization.

204128819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45876.

The product of its (nonzero) digits is 9216, while the sum is 35.

The square root of 204128819 is about 14287.3657124048. The cubic root of 204128819 is about 588.8004152926.

The spelling of 204128819 in words is "two hundred four million, one hundred twenty-eight thousand, eight hundred nineteen".