66565767221 has 8 divisors (see below), whose sum is σ = 66660471264. Its totient is φ = 66471107760.

The previous prime is 66565767197. The next prime is 66565767253. The reversal of 66565767221 is 12276756566.

It is a happy number.

66565767221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66565767221 is a prime.

It is a super-3 number, since 3×66565767221³ (a number of 33 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66565760221) 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, 3923126 + ... + 3940056.

It is an arithmetic number, because the mean of its divisors is an integer number (8332558908).

Almost surely, 2^66565767221 is an apocalyptic number.

It is an amenable number.

66565767221 is a deficient number, since it is larger than the sum of its proper divisors (94704043).

66565767221 is a wasteful number, since it uses less digits than its factorization.

66565767221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22291.

The product of its digits is 6350400, while the sum is 53.

The spelling of 66565767221 in words is "sixty-six billion, five hundred sixty-five million, seven hundred sixty-seven thousand, two hundred twenty-one".