28809471 has 4 divisors (see below), whose sum is σ = 38412632. Its totient is φ = 19206312.

The previous prime is 28809467. The next prime is 28809479. The reversal of 28809471 is 17490882.

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

It is not a de Polignac number, because 28809471 - 2² = 28809467 is a prime.

It is a super-3 number, since 3×28809471³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28809479) 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, 4801576 + ... + 4801581.

It is an arithmetic number, because the mean of its divisors is an integer number (9603158).

Almost surely, 2^28809471 is an apocalyptic number.

28809471 is a deficient number, since it is larger than the sum of its proper divisors (9603161).

28809471 is an equidigital number, since it uses as much as digits as its factorization.

28809471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9603160.

The product of its (nonzero) digits is 32256, while the sum is 39.

The square root of 28809471 is about 5367.4454817911. The cubic root of 28809471 is about 306.5573698148.

The spelling of 28809471 in words is "twenty-eight million, eight hundred nine thousand, four hundred seventy-one".