28228290 has 64 divisors (see below), whose sum is σ = 70778880. Its totient is φ = 7197120.

The previous prime is 28228289. The next prime is 28228307. The reversal of 28228290 is 9282282.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 117991 + ... + 118229.

It is an arithmetic number, because the mean of its divisors is an integer number (1105920).

Almost surely, 2^28228290 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28228290, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35389440).

28228290 is an abundant number, since it is smaller than the sum of its proper divisors (42550590).

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

28228290 is a wasteful number, since it uses less digits than its factorization.

28228290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407.

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 28228290 is about 5313.0302088356. The cubic root of 28228290 is about 304.4819297896.

The spelling of 28228290 in words is "twenty-eight million, two hundred twenty-eight thousand, two hundred ninety".