12121071666 has 48 divisors (see below), whose sum is σ = 26673628800. Its totient is φ = 3669288480.

The previous prime is 12121071661. The next prime is 12121071701. The reversal of 12121071666 is 66617012121.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (12121071661) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 746280 + ... + 762348.

It is an arithmetic number, because the mean of its divisors is an integer number (555700600).

Almost surely, 2^12121071666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 12121071666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13336814400).

12121071666 is an abundant number, since it is smaller than the sum of its proper divisors (14552557134).

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

12121071666 is a wasteful number, since it uses less digits than its factorization.

12121071666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17135 (or 17124 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 33.

Adding to 12121071666 its reverse (66617012121), we get a palindrome (78738083787).

The spelling of 12121071666 in words is "twelve billion, one hundred twenty-one million, seventy-one thousand, six hundred sixty-six".