2121100072 has 96 divisors (see below), whose sum is σ = 4985798400. Its totient is φ = 828202752.

The previous prime is 2121100021. The next prime is 2121100097. The reversal of 2121100072 is 2700011212.

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, 746238 + ... + 749074.

It is an arithmetic number, because the mean of its divisors is an integer number (51935400).

Almost surely, 2^2121100072 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2121100072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2492899200).

2121100072 is an abundant number, since it is smaller than the sum of its proper divisors (2864698328).

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

2121100072 is a wasteful number, since it uses less digits than its factorization.

2121100072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2955 (or 2938 counting only the distinct ones).

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 2121100072 is about 46055.4022021304. The cubic root of 2121100072 is about 1284.8538185540.

Adding to 2121100072 its reverse (2700011212), we get a palindrome (4821111284).

The spelling of 2121100072 in words is "two billion, one hundred twenty-one million, one hundred thousand, seventy-two".