55681840 has 80 divisors (see below), whose sum is σ = 134991360. Its totient is φ = 21344000.

The previous prime is 55681831. The next prime is 55681883. The reversal of 55681840 is 4818655.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-3 number, since 3×55681840³ (a number of 24 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 55681840.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 221715 + ... + 221965.

It is an arithmetic number, because the mean of its divisors is an integer number (1687392).

Almost surely, 2^55681840 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 55681840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67495680).

55681840 is an abundant number, since it is smaller than the sum of its proper divisors (79309520).

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

55681840 is a wasteful number, since it uses less digits than its factorization.

55681840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370 (or 364 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 37.

The square root of 55681840 is about 7462.0265343940. The cubic root of 55681840 is about 381.8603145975.

The spelling of 55681840 in words is "fifty-five million, six hundred eighty-one thousand, eight hundred forty".