28220775 has 48 divisors (see below), whose sum is σ = 51663360. Its totient is φ = 13478400.

The previous prime is 28220761. The next prime is 28220779. The reversal of 28220775 is 57702282.

It is not a de Polignac number, because 28220775 - 2⁶ = 28220711 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28220779) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 64959 + ... + 65391.

It is an arithmetic number, because the mean of its divisors is an integer number (1076320).

Almost surely, 2^28220775 is an apocalyptic number.

28220775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

28220775 is a deficient number, since it is larger than the sum of its proper divisors (23442585).

28220775 is a wasteful number, since it uses less digits than its factorization.

28220775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 536 (or 531 counting only the distinct ones).

The product of its (nonzero) digits is 15680, while the sum is 33.

The square root of 28220775 is about 5312.3229382258. The cubic root of 28220775 is about 304.4549074326.

It can be divided in two parts, 282207 and 75, that added together give a palindrome (282282).

The spelling of 28220775 in words is "twenty-eight million, two hundred twenty thousand, seven hundred seventy-five".