111221123261 has 2 divisors, whose sum is σ = 111221123262. Its totient is φ = 111221123260.

The previous prime is 111221123257. The next prime is 111221123267. The reversal of 111221123261 is 162321122111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 97150656100 + 14070467161 = 311690^2 + 118619^2 .

It is an emirp because it is prime and its reverse (162321122111) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 111221123261 - 2² = 111221123257 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111221123267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55610561630 + 55610561631.

It is an arithmetic number, because the mean of its divisors is an integer number (55610561631).

Almost surely, 2^111221123261 is an apocalyptic number.

It is an amenable number.

111221123261 is a deficient number, since it is larger than the sum of its proper divisors (1).

111221123261 is an equidigital number, since it uses as much as digits as its factorization.

111221123261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 288, while the sum is 23.

Adding to 111221123261 its reverse (162321122111), we get a palindrome (273542245372).

The spelling of 111221123261 in words is "one hundred eleven billion, two hundred twenty-one million, one hundred twenty-three thousand, two hundred sixty-one".