221166225 has 36 divisors (see below), whose sum is σ = 452726976. Its totient is φ = 101103840.

The previous prime is 221166223. The next prime is 221166269. The reversal of 221166225 is 522661122.

221166225 is a `hidden beast` number, since 2 + 21 + 16 + 622 + 5 = 666.

It is not a de Polignac number, because 221166225 - 2¹ = 221166223 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221166221) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 68637 + ... + 71786.

Almost surely, 2^221166225 is an apocalyptic number.

221166225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

221166225 is an abundant number, since it is smaller than the sum of its proper divisors (231560751).

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

221166225 is a wasteful number, since it uses less digits than its factorization.

221166225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140446 (or 140438 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 221166225 is about 14871.6584482027. The cubic root of 221166225 is about 604.7459033588.

The spelling of 221166225 in words is "two hundred twenty-one million, one hundred sixty-six thousand, two hundred twenty-five".