221206225 has 12 divisors (see below), whose sum is σ = 274897584. Its totient is φ = 176576720.

The previous prime is 221206213. The next prime is 221206267. The reversal of 221206225 is 522602122.

It is a happy number.

It is not a de Polignac number, because 221206225 - 2²³ = 212817617 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221206196 and 221206205.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2202 + ... + 21148.

It is an arithmetic number, because the mean of its divisors is an integer number (22908132).

Almost surely, 2^221206225 is an apocalyptic number.

221206225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

221206225 is a deficient number, since it is larger than the sum of its proper divisors (53691359).

221206225 is a wasteful number, since it uses less digits than its factorization.

221206225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19424 (or 19419 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 221206225 is about 14873.0032273243. The cubic root of 221206225 is about 604.7823591633.

Adding to 221206225 its reverse (522602122), we get a palindrome (743808347).

The spelling of 221206225 in words is "two hundred twenty-one million, two hundred six thousand, two hundred twenty-five".