1221310200821 has 2 divisors, whose sum is σ = 1221310200822. Its totient is φ = 1221310200820.

The previous prime is 1221310200811. The next prime is 1221310200841. The reversal of 1221310200821 is 1280020131221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1074840195025 + 146470005796 = 1036745^2 + 382714^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221310200821 - 2¹⁰ = 1221310199797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221310200811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610655100410 + 610655100411.

It is an arithmetic number, because the mean of its divisors is an integer number (610655100411).

Almost surely, 2^{1221310200821} is an apocalyptic number.

It is an amenable number.

1221310200821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221310200821 is an equidigital number, since it uses as much as digits as its factorization.

1221310200821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 23.

The spelling of 1221310200821 in words is "one trillion, two hundred twenty-one billion, three hundred ten million, two hundred thousand, eight hundred twenty-one".