243121220556 has 192 divisors, whose sum is σ = 633261888000. Its totient is φ = 72245899264.

The previous prime is 243121220491. The next prime is 243121220597. The reversal of 243121220556 is 655022121342.

It is a happy 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, 73161511 + ... + 73164833.

It is an arithmetic number, because the mean of its divisors is an integer number (3298239000).

Almost surely, 2^243121220556 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 243121220556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (316630944000).

243121220556 is an abundant number, since it is smaller than the sum of its proper divisors (390140667444).

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

243121220556 is a wasteful number, since it uses less digits than its factorization.

243121220556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3608 (or 3606 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 33.

Adding to 243121220556 its reverse (655022121342), we get a palindrome (898143341898).

The spelling of 243121220556 in words is "two hundred forty-three billion, one hundred twenty-one million, two hundred twenty thousand, five hundred fifty-six".