55621800 has 144 divisors (see below), whose sum is σ = 201250140. Its totient is φ = 13685760.

The previous prime is 55621777. The next prime is 55621801. The reversal of 55621800 is 812655.

It can be written as a sum of positive squares in 6 ways, for example, as 8259876 + 47361924 = 2874^2 + 6882^2 .

It is not an unprimeable number, because it can be changed into a prime (55621801) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 22212 + ... + 24588.

Almost surely, 2^55621800 is an apocalyptic number.

55621800 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 55621800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100625070).

55621800 is an abundant number, since it is smaller than the sum of its proper divisors (145628340).

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

55621800 is a wasteful number, since it uses less digits than its factorization.

55621800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2412 (or 2400 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 55621800 is about 7458.0024135153. The cubic root of 55621800 is about 381.7230158619.

The spelling of 55621800 in words is "fifty-five million, six hundred twenty-one thousand, eight hundred".