66008006606821 has 4 divisors (see below), whose sum is σ = 66304006636672. Its totient is φ = 65712006576972.

The previous prime is 66008006606803. The next prime is 66008006606923. The reversal of 66008006606821 is 12860660080066.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66008006606821 - 2¹¹ = 66008006604773 is a prime.

It is a super-2 number, since 2×66008006606821² (a number of 28 digits) contains 22 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 (66008006606021) 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, 148000014591 + ... + 148000015036.

It is an arithmetic number, because the mean of its divisors is an integer number (16576001659168).

Almost surely, 2^{66008006606821} is an apocalyptic number.

It is an amenable number.

66008006606821 is a deficient number, since it is larger than the sum of its proper divisors (296000029851).

66008006606821 is a wasteful number, since it uses less digits than its factorization.

66008006606821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 296000029850.

The product of its (nonzero) digits is 995328, while the sum is 49.

Adding to 66008006606821 its reverse (12860660080066), we get a palindrome (78868666686887).

The spelling of 66008006606821 in words is "sixty-six trillion, eight billion, six million, six hundred six thousand, eight hundred twenty-one".