66206221 has 8 divisors (see below), whose sum is σ = 68137344. Its totient is φ = 64296960.

The previous prime is 66206219. The next prime is 66206227. The reversal of 66206221 is 12260266.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66206221 - 2¹ = 66206219 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 (66206227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 781 + ... + 11533.

It is an arithmetic number, because the mean of its divisors is an integer number (8517168).

Almost surely, 2^66206221 is an apocalyptic number.

It is an amenable number.

66206221 is a deficient number, since it is larger than the sum of its proper divisors (1931123).

66206221 is a wasteful number, since it uses less digits than its factorization.

66206221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10931.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 66206221 is about 8136.7205310248. The cubic root of 66206221 is about 404.5444677546.

Adding to 66206221 its reverse (12260266), we get a palindrome (78466487).

The spelling of 66206221 in words is "sixty-six million, two hundred six thousand, two hundred twenty-one".