2121042400 has 144 divisors (see below), whose sum is σ = 5512709664. Its totient is φ = 794132480.

The previous prime is 2121042379. The next prime is 2121042419. The reversal of 2121042400 is 42401212.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3576504 + ... + 3577096.

It is an arithmetic number, because the mean of its divisors is an integer number (38282706).

Almost surely, 2^2121042400 is an apocalyptic number.

2121042400 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 2121042400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2756354832).

2121042400 is an abundant number, since it is smaller than the sum of its proper divisors (3391667264).

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

2121042400 is a wasteful number, since it uses less digits than its factorization.

2121042400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 893 (or 880 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 2121042400 is about 46054.7760824000. The cubic root of 2121042400 is about 1284.8421735336.

Adding to 2121042400 its reverse (42401212), we get a palindrome (2163443612).

The spelling of 2121042400 in words is "two billion, one hundred twenty-one million, forty-two thousand, four hundred".