221356897 has 6 divisors (see below), whose sum is σ = 233620818. Its totient is φ = 209706192.

The previous prime is 221356879. The next prime is 221356901. The reversal of 221356897 is 798653122.

It can be written as a sum of positive squares in only one way, i.e., 125238481 + 96118416 = 11191^2 + 9804^2 .

It is a de Polignac number, because none of the positive numbers 2^k-221356897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221356097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 306228 + ... + 306949.

It is an arithmetic number, because the mean of its divisors is an integer number (38936803).

Almost surely, 2^221356897 is an apocalyptic number.

It is an amenable number.

221356897 is a deficient number, since it is larger than the sum of its proper divisors (12263921).

221356897 is an equidigital number, since it uses as much as digits as its factorization.

221356897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 613215 (or 613196 counting only the distinct ones).

The product of its digits is 181440, while the sum is 43.

The square root of 221356897 is about 14878.0676500680. The cubic root of 221356897 is about 604.9196414454.

The spelling of 221356897 in words is "two hundred twenty-one million, three hundred fifty-six thousand, eight hundred ninety-seven".