28434809 has 4 divisors (see below), whose sum is σ = 30622116. Its totient is φ = 26247504.

The previous prime is 28434797. The next prime is 28434817. The reversal of 28434809 is 90843482.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90843482 = 2 ⋅45421741.

It can be written as a sum of positive squares in 2 ways, for example, as 18731584 + 9703225 = 4328^2 + 3115^2 .

It is a cyclic number.

It is not a de Polignac number, because 28434809 - 2²⁴ = 11657593 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28434839) 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, 1093634 + ... + 1093659.

It is an arithmetic number, because the mean of its divisors is an integer number (7655529).

Almost surely, 2^28434809 is an apocalyptic number.

It is an amenable number.

28434809 is a deficient number, since it is larger than the sum of its proper divisors (2187307).

28434809 is a wasteful number, since it uses less digits than its factorization.

28434809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2187306.

The product of its (nonzero) digits is 55296, while the sum is 38.

The square root of 28434809 is about 5332.4299339044. The cubic root of 28434809 is about 305.2226592346. Note that the first 3 decimals are identical.

The spelling of 28434809 in words is "twenty-eight million, four hundred thirty-four thousand, eight hundred nine".