208997221 has 4 divisors (see below), whose sum is σ = 209317932. Its totient is φ = 208676512.

The previous prime is 208997209. The next prime is 208997227. The reversal of 208997221 is 122799802.

208997221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 122799802 = 2 ⋅61399901.

It can be written as a sum of positive squares in 2 ways, for example, as 89094721 + 119902500 = 9439^2 + 10950^2 .

It is a cyclic number.

It is not a de Polignac number, because 208997221 - 2⁵ = 208997189 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 (208997227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 159376 + ... + 160681.

It is an arithmetic number, because the mean of its divisors is an integer number (52329483).

Almost surely, 2^208997221 is an apocalyptic number.

It is an amenable number.

208997221 is a deficient number, since it is larger than the sum of its proper divisors (320711).

208997221 is an equidigital number, since it uses as much as digits as its factorization.

208997221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320710.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 208997221 is about 14456.7361807567. The cubic root of 208997221 is about 593.4445837416. Note that the first 3 decimals are identical.

The spelling of 208997221 in words is "two hundred eight million, nine hundred ninety-seven thousand, two hundred twenty-one".