2121210920 has 64 divisors (see below), whose sum is σ = 5029992000. Its totient is φ = 802856448.

The previous prime is 2121210919. The next prime is 2121210937. The reversal of 2121210920 is 290121212.

It is a happy number.

It is a super-3 number, since 3×2121210920³ (a number of 29 digits) contains 333 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 2121210892 and 2121210901.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1107884 + ... + 1109796.

It is an arithmetic number, because the mean of its divisors is an integer number (78593625).

Almost surely, 2^2121210920 is an apocalyptic number.

2121210920 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 2121210920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2514996000).

2121210920 is an abundant number, since it is smaller than the sum of its proper divisors (2908781080).

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

2121210920 is a wasteful number, since it uses less digits than its factorization.

2121210920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3402 (or 3398 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 2121210920 is about 46056.6056065794. The cubic root of 2121210920 is about 1284.8762001784.

The spelling of 2121210920 in words is "two billion, one hundred twenty-one million, two hundred ten thousand, nine hundred twenty".