66080221 has 4 divisors (see below), whose sum is σ = 66136444. Its totient is φ = 66024000.

The previous prime is 66080171. The next prime is 66080227. The reversal of 66080221 is 12208066.

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 5707321 + 60372900 = 2389^2 + 7770^2 .

It is a cyclic number.

It is not a de Polignac number, because 66080221 - 2⁷ = 66080093 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66080227) 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, 26310 + ... + 28711.

It is an arithmetic number, because the mean of its divisors is an integer number (16534111).

Almost surely, 2^66080221 is an apocalyptic number.

It is an amenable number.

66080221 is a deficient number, since it is larger than the sum of its proper divisors (56223).

66080221 is a wasteful number, since it uses less digits than its factorization.

66080221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56222.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 66080221 is about 8128.9741665231. The cubic root of 66080221 is about 404.2876692621.

Adding to 66080221 its reverse (12208066), we get a palindrome (78288287).

The spelling of 66080221 in words is "sixty-six million, eighty thousand, two hundred twenty-one".