1221112000261 has 2 divisors, whose sum is σ = 1221112000262. Its totient is φ = 1221112000260.

The previous prime is 1221112000247. The next prime is 1221112000307. The reversal of 1221112000261 is 1620002111221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 770023800100 + 451088200161 = 877510^2 + 671631^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221112000261 - 2⁹ = 1221111999749 is a prime.

It is a super-2 number, since 2×1221112000261² (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 (1221112000061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610556000130 + 610556000131.

It is an arithmetic number, because the mean of its divisors is an integer number (610556000131).

Almost surely, 2^{1221112000261} is an apocalyptic number.

It is an amenable number.

1221112000261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221112000261 is an equidigital number, since it uses as much as digits as its factorization.

1221112000261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 19.

Adding to 1221112000261 its reverse (1620002111221), we get a palindrome (2841114111482).

The spelling of 1221112000261 in words is "one trillion, two hundred twenty-one billion, one hundred twelve million, two hundred sixty-one", and thus it is an aban number.