66118321 has 4 divisors (see below), whose sum is σ = 70007652. Its totient is φ = 62228992.

The previous prime is 66118301. The next prime is 66118333. The reversal of 66118321 is 12381166.

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 61858225 + 4260096 = 7865^2 + 2064^2 .

It is a cyclic number.

It is not a de Polignac number, because 66118321 - 2⁹ = 66117809 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66118321.

It is not an unprimeable number, because it can be changed into a prime (66118301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1944640 + ... + 1944673.

It is an arithmetic number, because the mean of its divisors is an integer number (17501913).

Almost surely, 2^66118321 is an apocalyptic number.

It is an amenable number.

66118321 is a deficient number, since it is larger than the sum of its proper divisors (3889331).

66118321 is a wasteful number, since it uses less digits than its factorization.

66118321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3889330.

The product of its digits is 1728, while the sum is 28.

The square root of 66118321 is about 8131.3172979536. The cubic root of 66118321 is about 404.3653546397.

Adding to 66118321 its reverse (12381166), we get a palindrome (78499487).

The spelling of 66118321 in words is "sixty-six million, one hundred eighteen thousand, three hundred twenty-one".