66566612321 has 4 divisors (see below), whose sum is σ = 72618122544. Its totient is φ = 60515102100.

The previous prime is 66566612317. The next prime is 66566612363. The reversal of 66566612321 is 12321666566.

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 66566612321 - 2² = 66566612317 is a prime.

It is a super-2 number, since 2×66566612321² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66566612381) 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, 3025755095 + ... + 3025755116.

It is an arithmetic number, because the mean of its divisors is an integer number (18154530636).

Almost surely, 2^66566612321 is an apocalyptic number.

It is an amenable number.

66566612321 is a deficient number, since it is larger than the sum of its proper divisors (6051510223).

66566612321 is a wasteful number, since it uses less digits than its factorization.

66566612321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6051510222.

The product of its digits is 466560, while the sum is 44.

The spelling of 66566612321 in words is "sixty-six billion, five hundred sixty-six million, six hundred twelve thousand, three hundred twenty-one".