1220355221 has 2 divisors, whose sum is σ = 1220355222. Its totient is φ = 1220355220.

The previous prime is 1220355211. The next prime is 1220355239. The reversal of 1220355221 is 1225530221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 885062500 + 335292721 = 29750^2 + 18311^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1220355221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1220355211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610177610 + 610177611.

It is an arithmetic number, because the mean of its divisors is an integer number (610177611).

Almost surely, 2^1220355221 is an apocalyptic number.

It is an amenable number.

1220355221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220355221 is an equidigital number, since it uses as much as digits as its factorization.

1220355221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 1220355221 is about 34933.5829968814. The cubic root of 1220355221 is about 1068.6334261507.

Adding to 1220355221 its reverse (1225530221), we get a palindrome (2445885442).

The spelling of 1220355221 in words is "one billion, two hundred twenty million, three hundred fifty-five thousand, two hundred twenty-one".