666221964184 has 256 divisors, whose sum is σ = 1537714080000. Its totient is φ = 270191738880.

The previous prime is 666221964173. The next prime is 666221964209. The reversal of 666221964184 is 481469122666.

It is a happy number.

It is a super-2 number, since 2×666221964184² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 600740622 + ... + 600741730.

It is an arithmetic number, because the mean of its divisors is an integer number (6006695625).

Almost surely, 2^666221964184 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666221964184, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (768857040000).

666221964184 is an abundant number, since it is smaller than the sum of its proper divisors (871492115816).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

666221964184 is a wasteful number, since it uses less digits than its factorization.

666221964184 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1331 (or 1313 counting only the distinct ones).

The product of its digits is 5971968, while the sum is 55.

The spelling of 666221964184 in words is "six hundred sixty-six billion, two hundred twenty-one million, nine hundred sixty-four thousand, one hundred eighty-four".