111912129 has 18 divisors (see below), whose sum is σ = 188043570. Its totient is φ = 63949536.

The previous prime is 111912127. The next prime is 111912133. The reversal of 111912129 is 921219111.

It can be written as a sum of positive squares in only one way, i.e., 105021504 + 6890625 = 10248^2 + 2625^2 .

It is not a de Polignac number, because 111912129 - 2¹ = 111912127 is a prime.

It is not an unprimeable number, because it can be changed into a prime (111912127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 126444 + ... + 127325.

It is an arithmetic number, because the mean of its divisors is an integer number (10446865).

Almost surely, 2^111912129 is an apocalyptic number.

It is an amenable number.

111912129 is a deficient number, since it is larger than the sum of its proper divisors (76131441).

111912129 is a wasteful number, since it uses less digits than its factorization.

111912129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253789 (or 253779 counting only the distinct ones).

The product of its digits is 324, while the sum is 27.

The square root of 111912129 is about 10578.8529151322. The cubic root of 111912129 is about 481.9023593706.

The spelling of 111912129 in words is "one hundred eleven million, nine hundred twelve thousand, one hundred twenty-nine".