1305220221 has 24 divisors (see below), whose sum is σ = 1929293184. Its totient is φ = 849925440.

The previous prime is 1305220171. The next prime is 1305220247. The reversal of 1305220221 is 1220225031.

It is not a de Polignac number, because 1305220221 - 2²² = 1301025917 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1305220194 and 1305220203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1305220291) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 228561 + ... + 234201.

It is an arithmetic number, because the mean of its divisors is an integer number (80387216).

Almost surely, 2^1305220221 is an apocalyptic number.

It is an amenable number.

1305220221 is a deficient number, since it is larger than the sum of its proper divisors (624072963).

1305220221 is a wasteful number, since it uses less digits than its factorization.

1305220221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6241 (or 6238 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 1305220221 is about 36127.8316675662. The cubic root of 1305220221 is about 1092.8517812813.

Adding to 1305220221 its reverse (1220225031), we get a palindrome (2525445252).

The spelling of 1305220221 in words is "one billion, three hundred five million, two hundred twenty thousand, two hundred twenty-one".