221378225 has 12 divisors (see below), whose sum is σ = 280351104. Its totient is φ = 173333520.

The previous prime is 221378221. The next prime is 221378249. The reversal of 221378225 is 522873122.

It is not a de Polignac number, because 221378225 - 2² = 221378221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 221378191 and 221378200.

It is not an unprimeable number, because it can be changed into a prime (221378221) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 93029 + ... + 95378.

It is an arithmetic number, because the mean of its divisors is an integer number (23362592).

Almost surely, 2^221378225 is an apocalyptic number.

221378225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

221378225 is a deficient number, since it is larger than the sum of its proper divisors (58972879).

221378225 is a wasteful number, since it uses less digits than its factorization.

221378225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188464 (or 188459 counting only the distinct ones).

The product of its digits is 13440, while the sum is 32.

The square root of 221378225 is about 14878.7843925504. The cubic root of 221378225 is about 604.9390690635.

The spelling of 221378225 in words is "two hundred twenty-one million, three hundred seventy-eight thousand, two hundred twenty-five".