55505551661550 has 384 divisors, whose sum is σ = 160767210240000. Its totient is φ = 14054385945600.

The previous prime is 55505551661507. The next prime is 55505551661591. The reversal of 55505551661550 is 5516615550555.

55505551661550 is a `hidden beast` number, since 5 + 5 + 5 + 0 + 5 + 5 + 5 + 16 + 615 + 5 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 11663278071 + ... + 11663282829.

It is an arithmetic number, because the mean of its divisors is an integer number (418664610000).

Almost surely, 2^{55505551661550} is an apocalyptic number.

55505551661550 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 55505551661550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80383605120000).

55505551661550 is an abundant number, since it is smaller than the sum of its proper divisors (105261658578450).

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

55505551661550 is a wasteful number, since it uses less digits than its factorization.

55505551661550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7473 (or 7462 counting only the distinct ones).

The product of its (nonzero) digits is 14062500, while the sum is 54.

The spelling of 55505551661550 in words is "fifty-five trillion, five hundred five billion, five hundred fifty-one million, six hundred sixty-one thousand, five hundred fifty".