28215305 has 8 divisors (see below), whose sum is σ = 34187712. Its totient is φ = 22352688.

The previous prime is 28215283. The next prime is 28215311. The reversal of 28215305 is 50351282.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28215305 - 2²⁰ = 27166729 is a prime.

It is a super-2 number, since 2×28215305² = 1592206872486050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26879 + ... + 27908.

It is an arithmetic number, because the mean of its divisors is an integer number (4273464).

Almost surely, 2^28215305 is an apocalyptic number.

It is an amenable number.

28215305 is a deficient number, since it is larger than the sum of its proper divisors (5972407).

28215305 is a wasteful number, since it uses less digits than its factorization.

28215305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54895.

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 28215305 is about 5311.8080725870. The cubic root of 28215305 is about 304.4352354480.

Adding to 28215305 its reverse (50351282), we get a palindrome (78566587).

The spelling of 28215305 in words is "twenty-eight million, two hundred fifteen thousand, three hundred five".