12121221042 has 72 divisors (see below), whose sum is σ = 30773727036. Its totient is φ = 3437892864.

The previous prime is 12121221041. The next prime is 12121221103. The reversal of 12121221042 is 24012212121.

It can be written as a sum of positive squares in 2 ways, for example, as 11465912241 + 655308801 = 107079^2 + 25599^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (12121221041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 70678 + ... + 170990.

Almost surely, 2^12121221042 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 12121221042, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15386863518).

12121221042 is an abundant number, since it is smaller than the sum of its proper divisors (18652505994).

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

12121221042 is a wasteful number, since it uses less digits than its factorization.

12121221042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100472 (or 100462 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 12121221042 its reverse (24012212121), we get a palindrome (36133433163).

The spelling of 12121221042 in words is "twelve billion, one hundred twenty-one million, two hundred twenty-one thousand, forty-two".