55217521920 has 288 divisors, whose sum is σ = 199021173120. Its totient is φ = 12924190720.

The previous prime is 55217521913. The next prime is 55217521937. The reversal of 55217521920 is 2912571255.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1202422 + ... + 1247498.

It is an arithmetic number, because the mean of its divisors is an integer number (691045740).

Almost surely, 2^55217521920 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 55217521920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99510586560).

55217521920 is an abundant number, since it is smaller than the sum of its proper divisors (143803651200).

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

55217521920 is a wasteful number, since it uses less digits than its factorization.

55217521920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45141 (or 45127 counting only the distinct ones).

The product of its (nonzero) digits is 63000, while the sum is 39.

The spelling of 55217521920 in words is "fifty-five billion, two hundred seventeen million, five hundred twenty-one thousand, nine hundred twenty".