66539121 has 16 divisors (see below), whose sum is σ = 101879040. Its totient is φ = 38203920.

The previous prime is 66539117. The next prime is 66539129. The reversal of 66539121 is 12193566.

It is a happy number.

It is not a de Polignac number, because 66539121 - 2² = 66539117 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (66539129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 52435 + ... + 53688.

It is an arithmetic number, because the mean of its divisors is an integer number (6367440).

Almost surely, 2^66539121 is an apocalyptic number.

It is an amenable number.

66539121 is a deficient number, since it is larger than the sum of its proper divisors (35339919).

66539121 is a wasteful number, since it uses less digits than its factorization.

66539121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106156.

The product of its digits is 9720, while the sum is 33.

The square root of 66539121 is about 8157.1515248891. The cubic root of 66539121 is about 405.2213817856.

The spelling of 66539121 in words is "sixty-six million, five hundred thirty-nine thousand, one hundred twenty-one".