209927221 has 6 divisors (see below), whose sum is σ = 244201110. Its totient is φ = 179937576.

The previous prime is 209927213. The next prime is 209927261. The reversal of 209927221 is 122729902.

It can be written as a sum of positive squares in only one way, i.e., 153512100 + 56415121 = 12390^2 + 7511^2 .

It is not a de Polignac number, because 209927221 - 2³ = 209927213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209927261) 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, 2142066 + ... + 2142163.

It is an arithmetic number, because the mean of its divisors is an integer number (40700185).

Almost surely, 2^209927221 is an apocalyptic number.

It is an amenable number.

209927221 is a deficient number, since it is larger than the sum of its proper divisors (34273889).

209927221 is an equidigital number, since it uses as much as digits as its factorization.

209927221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4284243 (or 4284236 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 209927221 is about 14488.8654145175. The cubic root of 209927221 is about 594.3235218351.

The spelling of 209927221 in words is "two hundred nine million, nine hundred twenty-seven thousand, two hundred twenty-one".