28220865 has 8 divisors (see below), whose sum is σ = 45153408. Its totient is φ = 15051120.

The previous prime is 28220849. The next prime is 28220879. The reversal of 28220865 is 56802282.

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

It is not a de Polignac number, because 28220865 - 2⁴ = 28220849 is a prime.

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, 940681 + ... + 940710.

It is an arithmetic number, because the mean of its divisors is an integer number (5644176).

Almost surely, 2^28220865 is an apocalyptic number.

It is an amenable number.

28220865 is a deficient number, since it is larger than the sum of its proper divisors (16932543).

28220865 is a wasteful number, since it uses less digits than its factorization.

28220865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1881399.

The product of its (nonzero) digits is 15360, while the sum is 33.

The square root of 28220865 is about 5312.3314090896. The cubic root of 28220865 is about 304.4552310820.

The spelling of 28220865 in words is "twenty-eight million, two hundred twenty thousand, eight hundred sixty-five".