55121356800 has 864 divisors, whose sum is σ = 209955858840. Its totient is φ = 13801881600.

The previous prime is 55121356753. The next prime is 55121356811. The reversal of 55121356800 is 865312155.

It is a happy number.

55121356800 is a `hidden beast` number, since 5 + 512 + 13 + 56 + 80 + 0 = 666.

It can be written as a sum of positive squares in 12 ways, for example, as 4528751616 + 50592605184 = 67296^2 + 224928^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 903628770 + ... + 903628830.

Almost surely, 2^55121356800 is an apocalyptic number.

55121356800 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 55121356800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104977929420).

55121356800 is an abundant number, since it is smaller than the sum of its proper divisors (154834502040).

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

55121356800 is a wasteful number, since it uses less digits than its factorization.

55121356800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189 (or 161 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 36.

Adding to 55121356800 its reverse (865312155), we get a palindrome (55986668955).

The spelling of 55121356800 in words is "fifty-five billion, one hundred twenty-one million, three hundred fifty-six thousand, eight hundred".