5518721688 has 64 divisors (see below), whose sum is σ = 14148781920. Its totient is φ = 1792742400.

The previous prime is 5518721657. The next prime is 5518721731. The reversal of 5518721688 is 8861278155.

It is a self number, because there is not a number n which added to its sum of digits gives 5518721688.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1096618 + ... + 1101638.

Almost surely, 2^5518721688 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 5518721688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7074390960).

5518721688 is an abundant number, since it is smaller than the sum of its proper divisors (8630060232).

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

5518721688 is a wasteful number, since it uses less digits than its factorization.

5518721688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6188 (or 6184 counting only the distinct ones).

The product of its digits is 1075200, while the sum is 51.

The square root of 5518721688 is about 74288.0992353419. The cubic root of 5518721688 is about 1767.1747503316.

The spelling of 5518721688 in words is "five billion, five hundred eighteen million, seven hundred twenty-one thousand, six hundred eighty-eight".