28004429 has 4 divisors (see below), whose sum is σ = 28463580. Its totient is φ = 27545280.

The previous prime is 28004419. The next prime is 28004437. The reversal of 28004429 is 92440082.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5299204 + 22705225 = 2302^2 + 4765^2 .

It is a cyclic number.

It is not a de Polignac number, because 28004429 - 2²⁴ = 11227213 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28004419) 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, 229484 + ... + 229605.

It is an arithmetic number, because the mean of its divisors is an integer number (7115895).

Almost surely, 2^28004429 is an apocalyptic number.

It is an amenable number.

28004429 is a deficient number, since it is larger than the sum of its proper divisors (459151).

28004429 is an equidigital number, since it uses as much as digits as its factorization.

28004429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 459150.

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 28004429 is about 5291.9211067438. The cubic root of 28004429 is about 303.6749071203.

The spelling of 28004429 in words is "twenty-eight million, four thousand, four hundred twenty-nine".