28307856 has 80 divisors (see below), whose sum is σ = 78369984. Its totient is φ = 8773632.

The previous prime is 28307837. The next prime is 28307879. The reversal of 28307856 is 65870382.

It is a super-2 number, since 2×28307856² = 1602669422633472, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 92055 + ... + 92361.

Almost surely, 2^28307856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28307856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39184992).

28307856 is an abundant number, since it is smaller than the sum of its proper divisors (50062128).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28307856 is a wasteful number, since it uses less digits than its factorization.

28307856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448 (or 442 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 39.

The square root of 28307856 is about 5320.5127572444. The cubic root of 28307856 is about 304.7677386098.

The spelling of 28307856 in words is "twenty-eight million, three hundred seven thousand, eight hundred fifty-six".