55999990000000 has 128 divisors (see below), whose sum is σ = 139452768000000. Its totient is φ = 22399992000000.

The previous prime is 55999989999949. The next prime is 55999990000001. The reversal of 55999990000000 is 9999955.

It is a tau number, because it is divible by the number of its divisors (128).

It is a zygodrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55999990000001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7200001 + ... + 12799999.

It is an arithmetic number, because the mean of its divisors is an integer number (1089474750000).

Almost surely, 2^{55999990000000} is an apocalyptic number.

55999990000000 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

55999990000000 is the 4000000-th nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 55999990000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (69726384000000).

55999990000000 is an abundant number, since it is smaller than the sum of its proper divisors (83452778000000).

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

55999990000000 is an frugal number, since it uses more digits than its factorization.

55999990000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5600048 (or 5600006 counting only the distinct ones).

The product of its (nonzero) digits is 1476225, while the sum is 55.

Adding to 55999990000000 its reverse (9999955), we get a palindrome (55999999999955).

The spelling of 55999990000000 in words is "fifty-five trillion, nine hundred ninety-nine billion, nine hundred ninety million", and thus it is an aban number.