55215400 has 48 divisors (see below), whose sum is σ = 130823100. Its totient is φ = 21665280.

The previous prime is 55215389. The next prime is 55215421. The reversal of 55215400 is 451255.

It can be written as a sum of positive squares in 6 ways, for example, as 43007364 + 12208036 = 6558^2 + 3494^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7996 + ... + 13204.

Almost surely, 2^55215400 is an apocalyptic number.

55215400 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 55215400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (65411550).

55215400 is an abundant number, since it is smaller than the sum of its proper divisors (75607700).

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

55215400 is a wasteful number, since it uses less digits than its factorization.

55215400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5278 (or 5269 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 22.

The square root of 55215400 is about 7430.7065612901. The cubic root of 55215400 is about 380.7910575366.

Adding to 55215400 its reverse (451255), we get a palindrome (55666655).

The spelling of 55215400 in words is "fifty-five million, two hundred fifteen thousand, four hundred".