111212312161 has 2 divisors, whose sum is σ = 111212312162. Its totient is φ = 111212312160.

The previous prime is 111212312131. The next prime is 111212312177. The reversal of 111212312161 is 161213212111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63111488400 + 48100823761 = 251220^2 + 219319^2 .

It is a cyclic number.

It is not a de Polignac number, because 111212312161 - 2⁷ = 111212312033 is a prime.

It is not a weakly prime, because it can be changed into another prime (111212312131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55606156080 + 55606156081.

It is an arithmetic number, because the mean of its divisors is an integer number (55606156081).

Almost surely, 2^111212312161 is an apocalyptic number.

It is an amenable number.

111212312161 is a deficient number, since it is larger than the sum of its proper divisors (1).

111212312161 is an equidigital number, since it uses as much as digits as its factorization.

111212312161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 144, while the sum is 22.

Adding to 111212312161 its reverse (161213212111), we get a palindrome (272425524272).

The spelling of 111212312161 in words is "one hundred eleven billion, two hundred twelve million, three hundred twelve thousand, one hundred sixty-one".