66111121 has 4 divisors (see below), whose sum is σ = 66187044. Its totient is φ = 66035200.

The previous prime is 66111109. The next prime is 66111163. The reversal of 66111121 is 12111166.

66111121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 37638225 + 28472896 = 6135^2 + 5336^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66111121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66111191) 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 3 ways as a sum of consecutive naturals, for example, 36640 + ... + 38401.

It is an arithmetic number, because the mean of its divisors is an integer number (16546761).

Almost surely, 2^66111121 is an apocalyptic number.

It is an amenable number.

66111121 is a deficient number, since it is larger than the sum of its proper divisors (75923).

66111121 is an equidigital number, since it uses as much as digits as its factorization.

66111121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75922.

The product of its digits is 72, while the sum is 19.

The square root of 66111121 is about 8130.8745532077. The cubic root of 66111121 is about 404.3506762258.

Adding to 66111121 its reverse (12111166), we get a palindrome (78222287).

The spelling of 66111121 in words is "sixty-six million, one hundred eleven thousand, one hundred twenty-one".