1221124305421 has 2 divisors, whose sum is σ = 1221124305422. Its totient is φ = 1221124305420.

The previous prime is 1221124305419. The next prime is 1221124305433. The reversal of 1221124305421 is 1245034211221.

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., 1210814136900 + 10310168521 = 1100370^2 + 101539^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221124305421 - 2¹ = 1221124305419 is a prime.

It is a super-2 number, since 2×1221124305421² (a number of 25 digits) contains 22 as substring.

Together with 1221124305419, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1221124305421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221124305451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610562152710 + 610562152711.

It is an arithmetic number, because the mean of its divisors is an integer number (610562152711).

Almost surely, 2^{1221124305421} is an apocalyptic number.

It is an amenable number.

1221124305421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221124305421 is an equidigital number, since it uses as much as digits as its factorization.

1221124305421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3840, while the sum is 28.

Adding to 1221124305421 its reverse (1245034211221), we get a palindrome (2466158516642).

The spelling of 1221124305421 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-four million, three hundred five thousand, four hundred twenty-one".