55681728 has 56 divisors (see below), whose sum is σ = 149230080. Its totient is φ = 18320640.

The previous prime is 55681721. The next prime is 55681729. The reversal of 55681728 is 82718655.

It is a self number, because there is not a number n which added to its sum of digits gives 55681728.

It is not an unprimeable number, because it can be changed into a prime (55681721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13333 + ... + 17003.

Almost surely, 2^55681728 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 55681728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (74615040).

55681728 is an abundant number, since it is smaller than the sum of its proper divisors (93548352).

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

55681728 is a wasteful number, since it uses less digits than its factorization.

55681728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3765 (or 3755 counting only the distinct ones).

The product of its digits is 134400, while the sum is 42.

The square root of 55681728 is about 7462.0190297265. The cubic root of 55681728 is about 381.8600585691.

The spelling of 55681728 in words is "fifty-five million, six hundred eighty-one thousand, seven hundred twenty-eight".