809128 has 8 divisors (see below), whose sum is σ = 1517130. Its totient is φ = 404560.

The previous prime is 809101. The next prime is 809141. The reversal of 809128 is 821908.

It can be written as a sum of positive squares in only one way, i.e., 580644 + 228484 = 762^2 + 478^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 809096 and 809105.

It is an unprimeable number.

809128 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50563 + ... + 50578.

2⁸⁰⁹¹²⁸ is an apocalyptic number.

It is an amenable number.

809128 is a deficient number, since it is larger than the sum of its proper divisors (708002).

809128 is a wasteful number, since it uses less digits than its factorization.

809128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101147 (or 101143 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 809128 is about 899.5154251040. The cubic root of 809128 is about 93.1835124672.

The spelling of 809128 in words is "eight hundred nine thousand, one hundred twenty-eight".