1221308104781 has 2 divisors, whose sum is σ = 1221308104782. Its totient is φ = 1221308104780.

The previous prime is 1221308104741. The next prime is 1221308104789. The reversal of 1221308104781 is 1874018031221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1191666973225 + 29641131556 = 1091635^2 + 172166^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221308104781 - 2¹⁴ = 1221308088397 is a prime.

It is a super-2 number, since 2×1221308104781² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221308104789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610654052390 + 610654052391.

It is an arithmetic number, because the mean of its divisors is an integer number (610654052391).

Almost surely, 2^{1221308104781} is an apocalyptic number.

It is an amenable number.

1221308104781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221308104781 is an equidigital number, since it uses as much as digits as its factorization.

1221308104781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21504, while the sum is 38.

The spelling of 1221308104781 in words is "one trillion, two hundred twenty-one billion, three hundred eight million, one hundred four thousand, seven hundred eighty-one".