1220001221 has 2 divisors, whose sum is σ = 1220001222. Its totient is φ = 1220001220.

The previous prime is 1220001199. The next prime is 1220001253. The reversal of 1220001221 is 1221000221.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1189905025 + 30096196 = 34495^2 + 5486^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220001221 - 2⁶ = 1220001157 is a prime.

1220001221 is a modest number, since divided by 1221 gives 1220 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1220001521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610000610 + 610000611.

It is an arithmetic number, because the mean of its divisors is an integer number (610000611).

Almost surely, 2^1220001221 is an apocalyptic number.

It is an amenable number.

1220001221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220001221 is an equidigital number, since it uses as much as digits as its factorization.

1220001221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 1220001221 is about 34928.5158717057. The cubic root of 1220001221 is about 1068.5300866173.

Adding to 1220001221 its reverse (1221000221), we get a palindrome (2441001442).

The spelling of 1220001221 in words is "one billion, two hundred twenty million, one thousand, two hundred twenty-one".