1221022021 has 2 divisors, whose sum is σ = 1221022022. Its totient is φ = 1221022020.

The previous prime is 1221022013. The next prime is 1221022031. The reversal of 1221022021 is 1202201221.

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., 963419521 + 257602500 = 31039^2 + 16050^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221022021 - 2³ = 1221022013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221021992 and 1221022010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221022031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610511010 + 610511011.

It is an arithmetic number, because the mean of its divisors is an integer number (610511011).

Almost surely, 2^1221022021 is an apocalyptic number.

It is an amenable number.

1221022021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221022021 is an equidigital number, since it uses as much as digits as its factorization.

1221022021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 1221022021 is about 34943.1255184764. The cubic root of 1221022021 is about 1068.8280238695.

Adding to 1221022021 its reverse (1202201221), we get a palindrome (2423223242).

The spelling of 1221022021 in words is "one billion, two hundred twenty-one million, twenty-two thousand, twenty-one".