28287823 has 4 divisors (see below), whose sum is σ = 28353888. Its totient is φ = 28221760.

The previous prime is 28287803. The next prime is 28287839. The reversal of 28287823 is 32878282.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32878282 = 2 ⋅16439141.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28287823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28287803) 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, 32386 + ... + 33247.

It is an arithmetic number, because the mean of its divisors is an integer number (7088472).

Almost surely, 2^28287823 is an apocalyptic number.

28287823 is a deficient number, since it is larger than the sum of its proper divisors (66065).

28287823 is an equidigital number, since it uses as much as digits as its factorization.

28287823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66064.

The product of its digits is 86016, while the sum is 40.

The square root of 28287823 is about 5318.6298047523. The cubic root of 28287823 is about 304.6958286200.

The spelling of 28287823 in words is "twenty-eight million, two hundred eighty-seven thousand, eight hundred twenty-three".