28212220 has 24 divisors (see below), whose sum is σ = 60508224. Its totient is φ = 11044416.

The previous prime is 28212211. The next prime is 28212221. The reversal of 28212220 is 2221282.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28212221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14067 + ... + 15946.

It is an arithmetic number, because the mean of its divisors is an integer number (2521176).

Almost surely, 2^28212220 is an apocalyptic number.

28212220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28212220 is an abundant number, since it is smaller than the sum of its proper divisors (32296004).

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

28212220 is a wasteful number, since it uses less digits than its factorization.

28212220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30069 (or 30067 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 28212220 is about 5311.5176738857. The cubic root of 28212220 is about 304.4241396151.

It can be divided in two parts, 2821 and 2220, that added together give a square (5041 = 71²).

The spelling of 28212220 in words is "twenty-eight million, two hundred twelve thousand, two hundred twenty".