2121055400 has 96 divisors (see below), whose sum is σ = 5230915200. Its totient is φ = 798124800.

The previous prime is 2121055393. The next prime is 2121055403. The reversal of 2121055400 is 45501212.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (2121055403) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 276821 + ... + 284379.

It is an arithmetic number, because the mean of its divisors is an integer number (54488700).

Almost surely, 2^2121055400 is an apocalyptic number.

2121055400 is a gapful number since it is divisible by the number (20) 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 2121055400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2615457600).

2121055400 is an abundant number, since it is smaller than the sum of its proper divisors (3109859800).

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

2121055400 is a wasteful number, since it uses less digits than its factorization.

2121055400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7659 (or 7650 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 2121055400 is about 46054.9172184686. The cubic root of 2121055400 is about 1284.8447984873.

Adding to 2121055400 its reverse (45501212), we get a palindrome (2166556612).

The spelling of 2121055400 in words is "two billion, one hundred twenty-one million, fifty-five thousand, four hundred".