208221221 has 4 divisors (see below), whose sum is σ = 224238252. Its totient is φ = 192204192.

The previous prime is 208221191. The next prime is 208221263. The reversal of 208221221 is 122122802.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 51696100 + 156525121 = 7190^2 + 12511^2 .

It is a cyclic number.

It is not a de Polignac number, because 208221221 - 2⁶ = 208221157 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 208221193 and 208221202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (208221271) 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, 8008496 + ... + 8008521.

It is an arithmetic number, because the mean of its divisors is an integer number (56059563).

Almost surely, 2^208221221 is an apocalyptic number.

It is an amenable number.

208221221 is a deficient number, since it is larger than the sum of its proper divisors (16017031).

208221221 is a wasteful number, since it uses less digits than its factorization.

208221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16017030.

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 208221221 is about 14429.8725219594. The cubic root of 208221221 is about 592.7091925722.

The spelling of 208221221 in words is "two hundred eight million, two hundred twenty-one thousand, two hundred twenty-one".