305220221 has 4 divisors (see below), whose sum is σ = 305255292. Its totient is φ = 305185152.

The previous prime is 305220173. The next prime is 305220229. The reversal of 305220221 is 122022503.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 1240996 + 303979225 = 1114^2 + 17435^2 .

It is a cyclic number.

It is not a de Polignac number, because 305220221 - 2¹⁰ = 305219197 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 305220221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (305220229) 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, 6515 + ... + 25551.

It is an arithmetic number, because the mean of its divisors is an integer number (76313823).

Almost surely, 2^305220221 is an apocalyptic number.

It is an amenable number.

305220221 is a deficient number, since it is larger than the sum of its proper divisors (35071).

305220221 is a wasteful number, since it uses less digits than its factorization.

305220221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35070.

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 305220221 is about 17470.5529677798. The cubic root of 305220221 is about 673.2935191688.

Adding to 305220221 its reverse (122022503), we get a palindrome (427242724).

The spelling of 305220221 in words is "three hundred five million, two hundred twenty thousand, two hundred twenty-one".