55121400 has 144 divisors (see below), whose sum is σ = 187443360. Its totient is φ = 14515200.

The previous prime is 55121393. The next prime is 55121401. The reversal of 55121400 is 412155.

55121400 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55121401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 203265 + ... + 203535.

It is an arithmetic number, because the mean of its divisors is an integer number (1301690).

Almost surely, 2^55121400 is an apocalyptic number.

55121400 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 55121400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93721680).

55121400 is an abundant number, since it is smaller than the sum of its proper divisors (132321960).

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

55121400 is a wasteful number, since it uses less digits than its factorization.

55121400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 406 (or 394 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 55121400 is about 7424.3787618898. The cubic root of 55121400 is about 380.5748455678.

Adding to 55121400 its reverse (412155), we get a palindrome (55533555).

The spelling of 55121400 in words is "fifty-five million, one hundred twenty-one thousand, four hundred".