28212225 has 24 divisors (see below), whose sum is σ = 46812480. Its totient is φ = 14992320.

The previous prime is 28212221. The next prime is 28212227. The reversal of 28212225 is 52221282.

It is not a de Polignac number, because 28212225 - 2² = 28212221 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28212195 and 28212204.

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 23 ways as a sum of consecutive naturals, for example, 28692 + ... + 29658.

It is an arithmetic number, because the mean of its divisors is an integer number (1950520).

Almost surely, 2^28212225 is an apocalyptic number.

28212225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28212225 is a deficient number, since it is larger than the sum of its proper divisors (18600255).

28212225 is a wasteful number, since it uses less digits than its factorization.

28212225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1369 (or 1364 counting only the distinct ones).

The product of its digits is 1280, while the sum is 24.

The square root of 28212225 is about 5311.5181445609. The cubic root of 28212225 is about 304.4241575992.

The spelling of 28212225 in words is "twenty-eight million, two hundred twelve thousand, two hundred twenty-five".